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Math Education
Learning Higher-Grade Math Ahead of Time is the Greatest Educational/Career Life Hack
Higher-grade math unlocks specialized fields that students normally couldn’t access until much later – and on average, the faster you accelerate your learning, the sooner you get your career started, and the more you accomplish over the course of your career. Read more...
Fortify Your F*cking Fundamentals
Skating around the rink will get you to a decent level of comfort in your basic skating skills, but being able to land jumps and spins will force a whole new level of robustness and fault-tolerance in those underlying skills. The same applies to knowledge in general. Read more...
The Best Mental Model for Serious Structured Learning
… is intense physical workouts. Read more...
You Can Effectively Turn Long-Term Memory Into An Extension of Working Memory
The way to do this is to develop automaticity on your lower-level skills. Read more...
The Worst Possible Way to Fail at Learning Math
… is to become an academic crank. Read more...
Why Math Educators Should Care About Talent Development
In math, de-prioritizing talent development leads to major issues. Read more...
Introduction to the Expertise Reversal Effect
Beginners (i.e., students) learn most effectively through direct instruction. Read more...
Yes, you need to spin up on foundational knowledge. No, you are not an exception.
Even Ramanujan self-studied. Read more...
Active Problem-Solving is Where The Learning Happens
Comfortable fluency in consuming information is not a proxy for actual learning. Read more...
How To Get a Full Time Software Job During College (5-Step Roadmap)
I worked full time in data science during my last 2 years of undergrad and I’m pretty sure the process to pull this off is reproducible. Read more...
Prereq Yo’ Self Before You Wreck Yo’ Self
If you hammer prerequisite concepts/skills into your long-term memory, get it really solid and easy to retrieve, then you can lessen the load on your working memory, keep it below capacity, avoid getting “broken,” and keep up with the game. Read more...
The Image I Want to Put in People’s Minds When They Think About Edtech
People acquiring impressive skills so quickly that it’s mind-bending. Read more...
The Pursuit of Real Life Superhero Training
I just want to build a thermodynamic machine that makes people insanely skilled as efficiently as possible. Read more...
It’s Memorization All The Way Down
At the end of the day all learning is memorization. Read more...
It’s Not About the Type of Motivation, It’s About the Total Amount of Motivation
Appreciation of mathematical beauty gets held up on too high a pedestal as the “correct” source of motivation in math learning. Read more...
The Future of Math Facts Practice on Math Academy
And the problem with many existing times tables practice systems. Read more...
Two of the Biggest Myths in Education
Myth 1: Understanding amounts to something other than memory. Myth 2: Sudents can perform high-level skills without mastering low-level component skills. Read more...
It’s Rare to Find Computation Walkthroughs in ML Learning Resources
Coding tutorials typically just say “import this function then run it,” and the math tutorials typically just say “this is the form of the model, you can fit it using the usual techniques” and leave it to the reader to figure out the rest. Read more...
Make it So Easy a Kid Can Learn It
If you can scaffold the content so well that it creates a smooth, efficient learning experience for knucklehead kids, it’s going to feel even smoother for more conscientious adults. Read more...
Selected Blog Posts About the State of Math Education
Specific areas of friction that cause students to struggle with math. What needs to be done to remove friction from the learning process. Why friction remains so prevalent. Read more...
Math is a Well-Defined Body of Knowledge
At the end of the day, whether or not they know math comes down to whether or not they can apply techniques within that well-defined body of knowledge to solve problems within that well-defined body of knowledge. Read more...
How To Mitigate Nonsense from Lazy/Adversarial Students
Enter grades early on, and (if pre-college) email parents early on. Read more...
The Necessity of Grinding Through Concrete Examples Before Jumping Up a Level of Abstraction
If you go directly to the most abstract ideas then you’re basically like a kid who reads a book of famous quotes about life and thinks they understand everything about life by way of those quotes. Read more...
Learning Math is Like Climbing a Ladder
… an infinitely tall ladder where the rungs get spaced further and further apart the higher you climb. Read more...
The Key to Learning Fast
… is reducing friction in the learning process. Read more...
What Math To Learn Next After Calculus
Depending on your goals, either A) methods of proof, or B) linear algebra followed by probability & statistics. Read more...
When Should Students Memorize Math Facts?
It’s helpful to loosely understand what something means before memorizing it, but this does not have to be a rigorous derivation. Read more...
“Learning” Info Without Practicing Reproducing it is Not Really Learning
It’s really just “loading” the info into temporary storage – like picking up a weight off the rack, whereas learning is increasing your ability to lift said weight. Read more...
Mistakes That Knowledgeable People Make When Teaching
1) Confusing “conceptually simple” with “notationally compact”, and 2) jumping to the most general method right away. Read more...
Hand Computation, Conceptual Debugging, and Coding Projects
The 3 types of problems that I would have students work out back when I was teaching ML. Read more...
Simple, Representative Concrete Examples
When an algorithm or process feels magical, that’s typically an indication you don’t really understand what’s happening under the hood. Read more...
Complete Individualization: an Often-Forgotten yet Critical Component of True Deliberate Practice
There are many studies demonstrating a benefit of some component of deliberate practice, but these studies often get mislabeled or misinterpreted as demonstrating the full benefit of true deliberate practice. The field of education is particularly susceptible to this issue because it is impossible for a teacher with a classroom of students to provide a true deliberate practice experience without assistive technology that perfectly emulates the one-on-one pedagogical decisions that an expert tutor would make for each individual student. Read more...
ML Courses can Vary Massively in their Coverage
I was coming in with the mindset of “we need to cover the superset of all the content covered in the major textbooks,” which we’re able to do quite well for traditional math. For ML, the rule will have to be amended to “we need to cover the superset of all the content covered in standard university course syllabi.” Read more...
Top-down’s fine for playing around. You’ll run into walls, but don’t give up — go bottom-up to get unstuck.
A little rhyme to understand the big picture of top-down vs bottom-up learning, particularly in the context of machine learning (ML). Read more...
Pictures are Valuable in Math Learning, but They’re Often Overvalued
Pictures can help build mathematical intuition, but sometimes learners think they should fully visualize every single problem they solve, which actually handicaps their thinking. Math involves generalizing patterns in logically consistent ways, and the generalizations eventually go beyond what you can fully picture in your head. Read more...
Why Talent Development is Necessary in Math
When students do the mathematical equivalent of playing kickball during class, and then are expected to do the mathematical equivalent of a backflip at the end of the year, it’s easy to see how struggle and general negative feelings can arise. Read more...
Some Pitfalls to Watch Out For when Learning From Projects
1) Don’t use projects as a way to acquire fundamental skills. 2) Make sure the projects are guided. 3) Don’t let the projects cut too much into your foundational skill-building. Read more...
You Are NOT Lazy, You Just Lack a Habit
The habit is a psychological force field that protects you from all sorts of negative feelings that try to dissuade you from training. Read more...
The “Alien-Level Skills” Hack
You get to provide value that nobody else can, and you get recognized for it. Read more...
Why I Recommend Students NOT Take Notes
If you try to keep information close by taking great notes that you can reference all the time… that just PREVENTS you from truly retaining it. Read more...
True active learning means…
every individual student is actively engaged on every piece of material to be learned. Read more...
How to Maximize Performance on a Standardized Math Test
If any student, anywhere, is looking for advice on how to prepare for a standardized math test, then this is everything I’d tell them. Read more...
How “Kicking the Can Down the Road” Happens in Education
It’s the tragedy of the commons. Read more...
What Math Students Need Beyond the “Why”
A comment to page 165 of Jo Boaler’s new book Math-ish Read more...
How to get from high school math to cutting-edge ML/AI: a detailed 4-stage roadmap with links to the best learning resources that I’m aware of.
1) Foundational math. 2) Classical machine learning. 3) Deep learning. 4) Cutting-edge machine learning. Read more...
Fast, Correct Answers Do Matter in Mathematics
You gotta develop automaticity on low-level skills in order to free up mental resources for higher-level thinking! Read more...
The Most Effective Way to Motivate Students to Learn Math
… is to not overwhelm them. In my experience, students naturally enjoy math when it doesn’t feel overwhelmingly difficult to learn. Read more...
How to Learn Machine Learning: Top Down or Bottom Up?
It can be helpful to take a top-down approach in planning out your overarching learning goals, but the learning itself has to occur bottom-up. Read more...
The Best Description of Explicit Instruction I’ve Ever Heard
Effective explicit instruction is all about clarity, and breaking down information, and minimizing the load on working memory. Read more...
The 2 Most Common Ways that People Get Retrieval Practice Wrong
1) The information must have already been written to memory. 2) The information must be retrieved from memory, unassisted. Read more...
Why Extrinsic Motivation Matters
I think optimal motivation requires a balance of both intrinsic and extrinsic factors. Read more...
What’s the Best Way to Teach Math: Explicit Instruction or Less Guided Learning?
Nobody who knows the science of learning is actually debating this. Read more...
Different Students Need Different Amounts of Practice
The amount of practice should be determined on the basis of each student’s individual performance on each individual topic. Some students may end up having to do more work, but this ultimately empowers them to learn and continue learning into the future. Read more...
When should you do math in your head vs writing it out on paper?
There is an asymmetric tradeoff between 1) blowing your working memory capacity and leaving yourself unable to make progress, versus 2) wasting a couple extra seconds writing down a bit more work than you need to. When in doubt, write it out. Read more...
Sources of Motivation in Successful Math Learners
I can think of 4 possible sources. Read more...
I’m Writing a Book on the Science of Learning (update: 400-page working draft is freely available)
With the science of learning, it’s less about “keeping up” with what’s happening, and more about “catching up” with what’s already happened. Read more...
How to Know When You are Practicing at the Edge of Your Ability
Most people can tell when their practice is too easy, but what about when your tasks are too hard? That’s often less obvious. Read more...
The Math Death Spiral: How Knowledge Gaps Lead to Student Failure
Accumulating mathematical knowledge gaps can lead students to reach a tipping point where further learning becomes overwhelming, ultimately causing them to abandon math entirely. Read more...
Learning Loss, Grade Inflation, and Radical Constructivism
The only way to argue against the existence of learning loss and grade inflation is to argue against the very idea of measuring learning objectively (i.e., radical constructivism). Read more...
“Following Along” vs Learning
You haven’t learned unless you’re able to consistently reproduce the information you consumed and use it to solve problems. Read more...
Why is the EdTech Industry So Damn Soft?
The hard truth is that if you want to build a serious educational product, you can’t be afraid to charge money for it. You can’t back yourself into a corner where you depend on a massive userbase. Why? Because most people are not serious about learning, and if you depend on a massive base of unserious learners, then you have to employ ineffective learning strategies that do not repel unserious students. Which makes your product suck. Read more...
The Pedagogically Optimal Way to Learn Math
The underlying principle that it all boils down to is deliberate practice. Read more...
The Issue with Watered-Down Math Courses
When students are not given the opportunity to learn math seriously, and are instead presented with watered-down courses and told that they’re doing a great job, they’re being set up for failure later in life when it matters most. Read more...
Who Needs Worked Examples? You, Eventually.
Math gets hard for different students at different levels. If you don’t have worked examples to help carry you through once math becomes hard for you, then every problem basically blows up into a “research project” for you. Sometimes people advocate for unguided struggle as a way to improve general problem-solving ability, but this idea lacks empirical support. Worked examples won’t prevent you from developing deep understanding (actually, it’s the opposite: worked examples can help you quickly layer on more skills, which forces a structural integrity in the lower levels of your knowledge). Even if you decide against using worked examples for now, continually re-evaluate to make sure you’re getting enough productive training volume. Read more...
Levels of Mathematics
Research mathematicians are like professional athletes. Read more...
How to Crush a Standardized Math Test: SAT/ACT, AP/IB, GRE/GMAT, JEE, etc.
First, you need extensive and solid content knowledge. Then, you need to work through tons of practice exams for the specific exam you’re taking. This might sound simple, but every year, countless people manage to screw it up. Read more...
The Most Superior Form of Training and the Most Hard-Hitting 2 Sentences in All of Talent Development Research
“…[D]eliberate practice requires effort and is not inherently enjoyable. Individuals are motivated to practice because practice improves performance.” Read more...
What is learning, at a physical level in the brain?
Long-term learning is represented by the creation of strategic electrical wiring between neurons. Read more...
If You Want to Learn Math, You Can’t Shy Away from Computation
Learning math with little computation is like learning basketball with little practice on dribbling & ball handling techniques. Read more...
Higher Math Textbooks and Classes are Typically Not Aligned with the Cognitive Science of Learning
Research indicates the best way to improve your problem-solving ability in any domain is simply by acquiring more foundational skills in that domain. The way you increase your ability to make mental leaps is not actually by jumping farther, but rather, by building bridges that reduce the distance you need to jump. Yet, higher math textbooks & courses seem to focus on trying to train jumping distance instead of bridge-building. Read more...
Why Not Just Learn from a Textbook, MIT OpenCourseWare, Khan Academy, etc.?
I learned from those kinds of resources myself, and while I came a long way, for the amount of effort I put into learning, I could have gone a lot further if my time were used more efficiently. That’s the problem that Math Academy solves. Read more...
The Problem with “Think Really Hard, Struggle for a While, Eventually Solve it or Look Up The Answer” Problems
Challenge problems are not a good use of time until you’ve developed the foundational skills that are necessary to grapple with these problems in a productive and timely fashion. Read more...
The Value of Foundational Math Knowledge in Machine Learning
If you start to flail (or, more subtly, doubt yourself and lose interest) after jumping into ML without a baseline level of foundational knowledge, then you need to put your ego aside and re-allocate your time into shoring up your foundations. Read more...
The Greatest Breakthrough in the Science of Education Over the Last Century
If you understand the interplay between working memory and long-term memory, then then you can actually derive – from first principles – the methods of effective teaching. Read more...
Conversational Dialogue is a Fascinating Distraction for AI in Education
Hard-coding explanations feels tedious, takes a lot of work, and isn’t “sexy” like an AI that generates responses from scratch – but at least it’s not a pipe dream. It’s a practical solution that lets you move on to other components of the AI that are just as important. Read more...
Paper Idea: A Theory of Optimal Learning Efficiency in Hierarchical Knowledge Structures
An idea for a paper that I don’t currently have the bandwidth to write. Read more...
Want to Major in Math at an Elite University? Getting A’s in High School Math is Not Good Enough
If all the knowledge you show up with is high school math and AP Calculus, and you’re not a genius, then you’re going to get your ass handed to you. Read more...
What People Think Maximum-Efficiency Learning Should Feel Like, vs What it Actually Feels Like
When you’re developing skills at peak efficiency, you are maximizing the difficulty of your training tasks subject to the constraint that you end up successfully overcoming those difficulties in a timely manner. Read more...
Review Should Feel Challenging
It’s the act of successfully retrieving fuzzy memory, not clear memory, that extends the memory duration. Read more...
The Vicious Cycle of Forgetting
To transfer information into long-term memory, you need to practice retrieving it without assistance. Read more...
Why 4x8 and 6x8 Are, Perhaps Surprisingly, Some of the Hardest Multiplication Facts for Students to Remember
There’s a cognitive principle behind this: associative interference, the phenomenon that conceptually related pieces of knowledge can interfere with each other’s recall. Read more...
When Does the Learning Happen?
Learning is the incremental gain in your ability to perform a tangible, reproducible skill. Read more...
Q&A: Does Self-Studying Advanced Math Create Bad Habits?
Sure, accelerating via self-study not as optimal as accelerating within teacher-managed courses, but it’s way better than not accelerating at all. Read more...
The Goal of Active Learning is NOT to Increase Cognitive Load
It’s actually the opposite – to get students actively retrieving information from memory, while minimizing their cognitive load. Read more...
Which Cognitive Psychology Findings are Solid, That Can Be Used to Help Students Learn Better?
There are numerous cognitive learning strategies that 1) can be used to massively improve learning, 2) have been reproduced so many times they might as well be laws of physics, and 3) connect all the way down to the mechanics of what’s going on in the brain. Read more...
If You Want to Learn Algebra, You Need to Have Automaticity on Basic Arithmetic
Solving equations feels smooth when basic arithmetic is automatic – it’s like moving puzzle pieces around, and you just need to identify how they fit together. But without automaticity on basic arithmetic, each puzzle piece is a heavy weight. You struggle to move them at all, much less figure out where they’re supposed to go. Read more...
What Mathematics Can Teach Us About Human Nature
It highlights the aversion that people have to doing hard things. People will do unbelievable mental gymnastics to convince themselves that doing an easy, enjoyable thing that is unrelated to their supposed goal somehow moves the needle more than doing a hard, unpleasant thing that is directly related to said goal. Read more...
What to Do When Math Gets Too Hard
In general, when you feel yourself running up against a ceiling in life, the solution is typically to pivot and into a direction where the ceiling is higher. Read more...
Lots of People in Education Disagree with the Premise of Maximizing Learning
But in talent development, the optimization problem is clear: an individual’s performance is to be maximized, so the methods used during practice are those that most efficiently convert effort into performance improvements. Read more...
There is No Such Thing as Low-Effort Learning
No matter what skill is being trained, improving performance is always an effortful process. Read more...
Spaced Repetition vs Spiraling
By periodically revisiting content, a spiral curriculum periodically restores forgotten knowledge and leverages the spacing effect to slow the decay of that knowledge. Spaced repetition takes this line of thought to its fullest extent by fully optimizing the review process. Read more...
Learning vs Feeling
The strongest people lift weights heavy enough to make them feel weak. Read more...
Leveraging Cognitive Learning Strategies Requires Technology
While there is plenty of room for teachers to make better use of cognitive learning strategies in the classroom, teachers are victims of circumstance in a profession lacking effective accountability and incentive structures, and the end result is that students continue to receive mediocre educational experiences. Given a sufficient degree of accountability and incentives, there is no law of physics preventing a teacher from putting forth the work needed to deliver an optimal learning experience to a single student. However, in the absence of technology, it is impossible for a single human teacher to deliver an optimal learning experience to a classroom of many students with heterogeneous knowledge profiles, each of whom needs to work on different types of problems and receive immediate feedback on each of their attempts. This is why technology is necessary. Read more...
The Utility of Gamification in Learning
Gamification, integrating game-like elements into learning environments, proves effective in increasing student learning, engagement, and enjoyment. Read more...
Cognitive Science of Learning: The Testing Effect (Retrieval Practice)
The testing effect (or the retrieval practice effect) emphasizes that recalling information from memory, rather than repeated reading, enhances learning. It can be combined with spaced repetition to produce an even more potent learning technique known as spaced retrieval practice. Read more...
Cognitive Science of Learning: Interleaving (Mixed Practice)
Interleaving (or mixed practice) involves spreading minimal effective doses of practice across various skills, in contrast to blocked practice, which involves extensive consecutive repetition of a single skill. Blocked practice can give a false sense of mastery and fluency because it allows students to settle into a robotic rhythm of mindlessly applying one type of solution to one type of problem. Interleaving, on the other hand, creates a “desirable difficulty” that promotes vastly superior retention and generalization, making it a more effective review strategy. But despite its proven efficacy, interleaving faces resistance in classrooms due to a preference for practice that feels easier and appears to produce immediate performance gains, even if those performance gains quickly vanish afterwards and do not carry over to test performance. Read more...
Cognitive Science of Learning: Spaced Repetition (Distributed Practice)
When reviews are spaced out or distributed over multiple sessions (as opposed to being crammed or massed into a single session), memory is not only restored, but also further consolidated into long-term storage, which slows its decay. This is known as the spacing effect. A profound consequence of the spacing effect is that the more reviews are completed (with appropriate spacing), the longer the memory will be retained, and the longer one can wait until the next review is needed. This observation gives rise to a systematic method for reviewing previously-learned material called spaced repetition (or distributed practice). A repetition is a successful review at the appropriate time. Read more...
Layering: Building Structural Integrity in Knowledge
Layering is the act of continually building on top of existing knowledge – that is, continually acquiring new knowledge that exercises prerequisite or component knowledge. This causes existing knowledge to become more ingrained, organized, and deeply understood, thereby increasing the structural integrity of a student’s knowledge base and making it easier to assimilate new knowledge. Read more...
Cognitive Science of Learning: Minimizing Associative Interference
Associative interference occurs when related knowledge interferes with recall. It is more likely to occur when highly related pieces of knowledge are learned simultaneously or in close succession. However, the effects of interference can be mitigated by teaching dissimilar concepts simultaneously and spacing out related pieces of knowledge over time. Read more...
Cognitive Science of Learning: Developing Automaticity
Automaticity is the ability to perform low-level skills without conscious effort. Analogous to a basketball player effortlessly dribbling while strategizing, automaticity allows individuals to avoid spending limited cognitive resources on low-level tasks and instead devote those cognitive resources to higher-order reasoning. In this way, automaticity is the gateway to expertise, creativity, and general academic success. However, insufficient automaticity, particularly in basic skills, inflates the cognitive load of tasks, making it exceedingly difficult for students to learn and perform. Read more...
Cognitive Science of Learning: Minimizing Cognitive Load
Different students have different working memory capacities. When the cognitive load of a learning task exceeds a student’s working memory capacity, the student experiences cognitive overload and is not able to complete the task. Read more...
A Brief History of Mastery Learning
Mastery learning is a strategy in which students demonstrate proficiency on prerequisites before advancing. While even loose approximations of mastery learning have been shown to produce massive gains in student learning, mastery learning faces limited adoption due to clashing with traditional teaching methods and placing increased demands on educators. True mastery learning at a fully granular level requires fully individualized instruction and is only attainable through one-on-one tutoring. Read more...
Deliberate Practice: The Most Effective Form of Active Learning
Deliberate practice is the most effective form of active learning. It consists of individualized training activities specially chosen to improve specific aspects of a student’s performance through repetition and successive refinement. It is mindful repetition at the edge of one’s ability, the opposite of mindless repetition within one’s repertoire. The amount of deliberate practice has been shown to be one of the most prominent underlying factors responsible for individual differences in performance across numerous fields, even among highly talented elite performers. Deliberate practice demands effort and intensity, and may be discomforting, but its long-term commitment compounds incremental improvements, leading to expertise. Read more...
The Neuroscience of Active Learning and Automaticity
Active learning leads to more neural activation than passive learning. Automaticity involves developing strategic neural connections that reduce the amount of effort that the brain has to expend to activate patterns of neurons. Read more...
Active Learning: If You’re Active Half the Time, That’s Still Not Enough
During practice, the elite skaters were over 6 times more active than passive, while non-competitive skaters were nearly as passive as they were active. Read more...
Most Students Don’t Even Pay Attention During Lectures
A startup spent months building a sophisticated lecture tool and raising over half a million dollars in investments – but after observing students in the lecture hall, they completely abandoned the product and called up their investors to return the money. Read more...
What Counts as Active Learning?
True active learning requires every individual student to be actively engaged on every piece of the material to be learned. Read more...
What To Do Leading Up to a Standardized Exam Like AP Calculus BC
Six weeks of pure review and six official practice exams. Read more...
The Double-Edged Nature of Hierarchical Knowledge
It’s easier to run into roadblocks, but also easier to maintain what you’ve learned. Read more...
You Know it’s Edutainment When…
Passive consumption. Lack of depth. Lack of rigorous assessments. Failing upwards. Lack of skill development. Read more...
Why Poking Around Wikipedia Doesn’t Move The Needle on Math Learning
It’s like going to the gym without a solid workout plan in place. Read more...
How Much Math Do You Need to Know for Machine Learning?
If you know your single-variable calculus, then it’s about 70 hours on Math Academy. Read more...
Your Mathematical Potential Has a Limit, but it’s Likely Higher Than You Think
Not everybody can learn every level of math, but most people can learn the basics. In practice, however, few people actually reach their full mathematical potential because they get knocked off course early on by factors such as missing foundations, ineffective practice habits, inability or unwillingness to engage in additional practice, or lack of motivation. Read more...
The Greatest Educational Life Hack: Learning Math Ahead of Time
Learning math early guards you against numerous academic risks and opens all kinds of doors to career opportunities. Read more...
Myths and Realities about Educational Acceleration
Acceleration does not lead to adverse psychological consequences in capable students; rather, whether a student is ready for advanced mathematics depends solely on whether they have mastered the prerequisites. Acceleration does not imply shallowness of learning; rather, students undergoing acceleration generally learn – in a shorter time – as much as they would otherwise in a non-accelerated environment over a proportionally longer period of time. Accelerated students do not run out of courses to take and are often able to place out of college math courses even beyond what is tested on placement exams. Lastly, for students who have the potential to capitalize on it, acceleration is the greatest educational life hack: the resulting skills and opportunities can rocket students into some of the most interesting, meaningful, and lucrative careers, and the early start can lead to greater career success. Read more...
Effective Learning Requires Intense Effort
Effortful processes like testing, repetition, and computation are essential parts of effective learning, and competition is often helpful. Read more...
Effective Learning Does Not Emulate the Professional Workplace
The most effective learning techniques require substantial cognitive effort from students and typically do not emulate what experts do in the professional workplace. Direct instruction is necessary to maximize student learning, whereas unguided instruction and group projects are typically very inefficient. Read more...
People Differ in Learning Speed, Not Learning Style
Different people generally have different working memory capacities and learn at different rates, but people do not actually learn better in their preferred “learning style.” Instead, different people need the same form of practice but in different amounts. Read more...
Accountability and Incentives are Necessary but Absent in Education
Students and teachers are often not aligned with the goal of maximizing learning, which means that in the absence of accountability and incentives, classrooms are pulled towards a state of mediocrity. Accountability and incentives are typically absent in education, which leads to a “tragedy of the commons” situation where students pass courses (often with high grades) despite severely lacking knowledge of the content. Read more...
The Story of the Science of Learning
In terms of improving educational outcomes, science is not where the bottleneck is. The bottleneck is in practice. The science of learning has advanced significantly over the past century, yet the practice of education has barely changed. Read more...
Cognitive Science of Learning: How the Brain Works
Cognition involves the flow of information through sensory, working, and long-term memory banks in the brain. Sensory memory temporarily holds raw data, working memory manipulates and organizes information, and long-term memory stores it indefinitely by creating strategic electrical wiring between neurons. Learning amounts to increasing the quantity, depth, retrievability, and generalizability of concepts and skills in a student’s long-term memory. Limited working memory capacity creates a bottleneck in the transfer of information into long-term memory, but cognitive learning strategies can be used to mitigate the effects of this bottleneck. Read more...
Talent Development vs Traditional Schooling
Talent development is not only different from schooling, but in many cases completely orthogonal to schooling. Read more...
Bloom’s Two-Sigma Problem
The average tutored student performed better than 98% of students in the traditional class. Read more...
The Tragedy of the Commons in Education
Why it’s common for students to pass courses despite severely lacking knowledge of the content. Read more...
Optimized, Individualized Spaced Repetition in Hierarchical Knowledge Structures
Spaced repetition is complicated in hierarchical bodies of knowledge, like mathematics, because repetitions on advanced topics should “trickle down” to update the repetition schedules of simpler topics that are implicitly practiced (while being discounted appropriately since these repetitions are often too early to count for full credit towards the next repetition). However, I developed a model of Fractional Implicit Repetition (FIRe) that not only accounts for implicit “trickle-down” repetitions but also minimizes the number of reviews by choosing reviews whose implicit repetitions “knock out” other due reviews (like dominos), and calibrates the speed of the spaced repetition process to each individual student on each individual topic (student ability and topic difficulty are competing factors). Read more...
Blog
(In Progress) Advice on Upskilling
You’re Not Lazy, You Just Lack a Habit • Don’t have a passion? Go create one. • Make the Habit Easily Repeatable • Don’t Overreact to Bad Days • Aim for Virtuous Cycles • The Importance of Hardcore Skills • Fortify Your F*cking Fundamentals • Why Train? • The Magic You’re Looking For is in the Full-Assed Effort You’re Avoiding • At some point Doing the Hard Thing becomes Easier than Making the Hard Thing Easier • How to Cultivate Discipline • Keep Your Hands On The Boulder Read more...
Introduction to the Expertise Reversal Effect
Beginners (i.e., students) learn most effectively through direct instruction. Read more...
The Best Neural Nets Textbook That I’ve Seen So Far
“Understanding Deep Learning” by Simon J. D. Prince Read more...
The Image I Want to Put in People’s Minds When They Think About Edtech
People acquiring impressive skills so quickly that it’s mind-bending. Read more...
Top 3 Skills
Math, coding, communication. Read more...
On Writing Good Code
It’s kind of amusing how some (novice) devs will boast/revel at how many lines of code they wrote while simultaneously cramming each line full with as much complexity as they can hold in working memory. Read more...
The One Skill You Can Acquire By Passively Consuming Information
The ability to say things that sound smart on the surface without actually knowing what you’re talking about. Read more...
Two of the Biggest Myths in Education
Myth 1: Understanding amounts to something other than memory. Myth 2: Sudents can perform high-level skills without mastering low-level component skills. Read more...
Learning Math is Like Climbing a Ladder
… an infinitely tall ladder where the rungs get spaced further and further apart the higher you climb. Read more...
The Key to Learning Fast
… is reducing friction in the learning process. Read more...
Hand Computation, Conceptual Debugging, and Coding Projects
The 3 types of problems that I would have students work out back when I was teaching ML. Read more...
Simple, Representative Concrete Examples
When an algorithm or process feels magical, that’s typically an indication you don’t really understand what’s happening under the hood. Read more...
ML Courses can Vary Massively in their Coverage
I was coming in with the mindset of “we need to cover the superset of all the content covered in the major textbooks,” which we’re able to do quite well for traditional math. For ML, the rule will have to be amended to “we need to cover the superset of all the content covered in standard university course syllabi.” Read more...
How to Maximize Performance on a Standardized Math Test
If any student, anywhere, is looking for advice on how to prepare for a standardized math test, then this is everything I’d tell them. Read more...
What Math Students Need Beyond the “Why”
A comment to page 165 of Jo Boaler’s new book Math-ish Read more...
The Most Effective Way to Motivate Students to Learn Math
… is to not overwhelm them. In my experience, students naturally enjoy math when it doesn’t feel overwhelmingly difficult to learn. Read more...
Intuition Behind Polynomial Numerators in Partial Fractions
Each decomposition produces a system of linear equations where the number of unknowns equals the number of equations. Read more...
Sources of Motivation in Successful Math Learners
I can think of 4 possible sources. Read more...
How do you apply math to CS when so many software engineers say that there is not that much math in coding?
Write code that makes complicated decisions, often involving some kind of inference. Read more...
What’s the Highest Sustainable Daily XP on Math Academy?
Around 50-60 XP/day, that is, 50-60 minutes of serious practice per day. Just like the high-end amount of daily exercise you’d expect from people who keep a consistent exercise routine at the gym. Read more...
How to Know When You are Practicing at the Edge of Your Ability
Most people can tell when their practice is too easy, but what about when your tasks are too hard? That’s often less obvious. Read more...
Trick to Check Equality of Expression Containing Subscripts Using a Basic LaTeX Expression Evaluator
A silly bug turned genius hack. Read more...
Learning Loss, Grade Inflation, and Radical Constructivism
The only way to argue against the existence of learning loss and grade inflation is to argue against the very idea of measuring learning objectively (i.e., radical constructivism). Read more...
Record for Most Work Done on Math Academy on a Single Date (as of July 2024)
834 XP = 834 minutes = 14 hours of work in a single day. You’re probably wondering, what kind of person does that much math in a day? Time for a little story. Read more...
Levels of Mathematics
Research mathematicians are like professional athletes. Read more...
What is learning, at a physical level in the brain?
Long-term learning is represented by the creation of strategic electrical wiring between neurons. Read more...
Individual Variation in Working Memory Capacity (WMC): a First Step Down the Research Rabbit Hole
There are many, many studies that measure variation in WMC vs variation in other metrics. Read more...
The Value of Foundational Math Knowledge in Machine Learning
If you start to flail (or, more subtly, doubt yourself and lose interest) after jumping into ML without a baseline level of foundational knowledge, then you need to put your ego aside and re-allocate your time into shoring up your foundations. Read more...
The Tip of Math Academy’s Technical Iceberg
Our AI system is one of those things that sounds intuitive enough at a high level, but if you start trying to implement it yourself, you quickly run into a mountain of complexity, numerous edge cases, lots of counterintuitive low-level phenomena that take a while to fully wrap your head around. Read more...
Paper Idea: A Theory of Optimal Learning Efficiency in Hierarchical Knowledge Structures
An idea for a paper that I don’t currently have the bandwidth to write. Read more...
When Does the Learning Happen?
Learning is the incremental gain in your ability to perform a tangible, reproducible skill. Read more...
The Goal of Active Learning is NOT to Increase Cognitive Load
It’s actually the opposite – to get students actively retrieving information from memory, while minimizing their cognitive load. Read more...
A Quick Trick for Finding a Matrix Transformation Formula
Perform the desired transformation on identity matrix to get a left-multiplier, and maybe transpose the output. Read more...
Bloom’s 3 Stages of Talent Development
First, fun and exciting playtime. Then, intense and strenuous skill development. Finally, developing one’s individual style while pushing the boundaries of the field. Read more...
What Mathematics Can Teach Us About Human Nature
It highlights the aversion that people have to doing hard things. People will do unbelievable mental gymnastics to convince themselves that doing an easy, enjoyable thing that is unrelated to their supposed goal somehow moves the needle more than doing a hard, unpleasant thing that is directly related to said goal. Read more...
What to Do When Math Gets Too Hard
In general, when you feel yourself running up against a ceiling in life, the solution is typically to pivot and into a direction where the ceiling is higher. Read more...
Estimating a Visitation Interval: an Exercise in Bivariate Bayesian Statistics
Loosely inspired by the German tank problem: several witnesses reported seeing a UFO during the given time intervals, and you want to quantify your certainty regarding when the UFO arrived and when it left. Read more...
Recreational Mathematics: Why Focus on Projects Over Puzzles
There’s only so much fun you can have trying to follow another person’s footsteps to arrive at a known solution. There’s only so much confidence you can build from fighting against a problem that someone else has intentionally set up to be well-posed and elegantly solvable if you think about it the right way. Read more...
Intuiting Adversarial Examples in Neural Networks via a Simple Computational Experiment
The network becomes book-smart in a particular area but not street-smart in general. The training procedure is like a series of exams on material within a tiny subject area (your data subspace). The network refines its knowledge in the subject area to maximize its performance on those exams, but it doesn’t refine its knowledge outside that subject area. And that leaves it gullible to adversarial examples using inputs outside the subject area. Read more...
Should Students be Asked to Regurgitate Known Proofs?
Imitating without analyzing produces a robot / ape who can’t think critically; analyzing without imitating produces a critic who can’t act on their own advice. Read more...
Most Students Don’t Even Pay Attention During Lectures
A startup spent months building a sophisticated lecture tool and raising over half a million dollars in investments – but after observing students in the lecture hall, they completely abandoned the product and called up their investors to return the money. Read more...
What To Do Leading Up to a Standardized Exam Like AP Calculus BC
Six weeks of pure review and six official practice exams. Read more...
Subtle Things to Watch Out For When Demonstrating Lp-Norm Regularization on a High-Degree Polynomial Regression Model
Initial parameter range, data sampling range, severity of regularization. Read more...
Why Poking Around Wikipedia Doesn’t Move The Needle on Math Learning
It’s like going to the gym without a solid workout plan in place. Read more...
How Much Math Do You Need to Know for Machine Learning?
If you know your single-variable calculus, then it’s about 70 hours on Math Academy. Read more...
The Only Way to Teach a More Sophisticated Technique
… is to present a problem where known simpler techniques fail. Read more...
How I Got Started with Calisthenics
My training has been scattered and fuzzy until recently. Here’s the whole story. Read more...
The Easiest Way to Remember Closed vs Open Interval Notation
An oval () fits inside a rectangle [ ] with the same width and height. Read more...
Bloom’s Two-Sigma Problem
The average tutored student performed better than 98% of students in the traditional class. Read more...
A Common Source of Student Mistakes
Many students who pattern-match will tend to prefer solutions requiring fewer and simpler operations, especially if those solutions yield ballpark-reasonable results. Read more...
Ambiguous Absolute Value Expressions
Is there a standard “order of operations” for parallel vs nested absolute value expressions, in the absence of clarifying notation? Read more...
My Go-To Math Riddle: How Many Squares are in a 10 x 10 Grid?
Q: Draw a 10 x 10 square grid. How many squares are there in total? Not just 1 x 1 squares, but also 2 x 2 squares, 3 x 3 squares, and so on. A: The total number of square shapes is the total sum of square numbers 1 + 4 + 9 + 16 + … + 100. Read more...
Study Sessions Should be Short and Frequent as Opposed to Long and Sparse
First, you want to form a habit. Second, you want to operate at peak productivity during your session. Third, you want to minimize the amount you forget between sessions. Read more...
Educational resources commonly address slant asymptotes. Why not general polynomial asymptotes?
Answer: It’s not very useful (not in practice, not in theory). Read more...
Can You Automate a Math Teacher?
For many (but not all) students, the answer is yes. And for many of those students, automation can unlock life-changing educational outcomes. Read more...
The Abstraction Ceiling: Why it’s Hard to Teach First-Principles Reasoning
As you climb the levels of math, sources of educational friction conspire against you and eventually throw you off the train. And one of the first warning signs is when you stop understanding things at the core, and instead try to memorize special cases cookbook-style. Read more...
When Can You Manipulate Differentials Like Fractions?
In general, you can manipulate total derivatives like fractions, but you can’t do the same with partial derivatives. Read more...
How to Look Up the Meaning of an Unknown Math Symbol or Expression
Drawing –> Latex commands –> ChatGPT summary –> Google more info Read more...
How to Remember Type I, II, and III Regions in Multivariable Calculus
Type I pairs with the variable that runs vertically in the usual representation of the coordinate system. The remaining types are paired with the rest of the variables in ascending order. Read more...
Minimalist Strength Training, Phase 2: Gaining Mass
Minor changes to increase workout intensity and caloric surplus. Read more...
Minimalist Strength Training, Phase 1: Getting Ripped
Daily 20-30 minute bedroom workout with gymnastic rings hanging from pull-up bar – just as much challenge as weights, but inexpensive and easily portable. Read more...
Quants vs Systems Coders
Two subtypes of coders that I watched students grow into. Read more...
Memory vs Time Graphs
A way to visualize some cognitive learning strategies. Read more...
The 5 Breeds of Quants
… are summarized in the following table. Read more...
From Procedures to Objects
An aha moment with object-oriented programming. Read more...
The Ultimate High School Computer Science Sequence: 9 Months In
In 9 months, these students went from initially not knowing how to write helper functions to building a machine learning library from scratch. Read more...
Tips for LaTeX Math Formatting
How to avoid some of the most common pitfalls leading to ugly LaTeX. Read more...
Path Dependency in Multivariable Limits
The behavior of a multivariable function can be highly specific to the path taken. Read more...
Thales’ Theorem
Every inscribed triangle whose hypotenuse is a diameter is a right triangle. Read more...
Trick to Apply the Chain Rule FAST - Peeling the Onion
A simple mnemonic trick for quickly differentiating complicated functions. Read more...
CheckMySteps: A Web App to Help Students Fix their Algebraic Mistakes
A prototype web app to automatically assist students in self-correcting small errors and minor misconceptions. Read more...
Solving Tower of Hanoi with General Problem Solver
A walkthrough of solving Tower of Hanoi using the approach of one of the earliest AI systems. Read more...
A Game-Theoretic Analysis of Social Distancing During Epidemics
In a simplified problem framing, we investigate the (game-theoretical) usefulness of limiting the number of social connections per person. Read more...
Making Indirect Interactions Explicit in Networks
Category theory provides a language for explicitly describing indirect relationships in graphs. Read more...
Book Summary: Memory Evolutive Systems
Framing complex systems in the language of category theory. Read more...
Introduction to Computers
The main ideas behind computers can be understood by anyone. Read more...
The Brain in One Sentence
The brain is a neuronal network integrating specialized subsystems that use local competition and thresholding to sparsify input, spike-timing dependent plasticity to learn inference, and layering to implement hierarchical predictive learning. Read more...
Shaping STDP Neural Networks with Periodic Stimulation: a Theoretical Analysis for the Case of Tree Networks
We solve a special case of how to periodically stimulate a biological neural network to obtain a desired connectivity (in theory). Read more...
On the Contrasting Educations and Outcomes of Ben Franklin and Montaigne
Montaigne’s education, strictly dictated by his parents and university studies, resulted in an isolative work with scholarly impact but limited public reach. Conversely, Benjamin Franklin’s goal-oriented self-teaching led to influential creations and roles benefiting his community and nation. Read more...
A Brief Overview of Spike-Timing Dependent Plasticity (STDP) Learning During Neural Simulation
Implementation notes for STDP learning in a network of Hodgkin-Huxley simulated neurons. Read more...
A Visual, Inductive Proof of Sharkovsky’s Theorem
Many existing proofs are not accessible to young mathematicians or those without experience in the realm of dynamic systems. Read more...
Building an Iron Man Suit: A Physics Workbook
A workbook I created to explain the math and physics behind an Iron Man suit to a student who was interested in the comics / movies. Read more...
The Physics Behind an Egg Drop: A Lively Story
A workbook I created to explain the math and physics behind an egg drop experiment to a student who was interested in Lord of the Rings and Star Wars. Read more...
A Formula for the Partial Fractions Decomposition of $x^n/(x-a)^k$
And a proof via double induction. Read more...
Sound Waves
A brief overview of sound waves and how they interact with things. Read more...
Detecting Dark Matter
A brief overview of the experimental search for dark matter (XENON, CDMS, PICASSO, COUPP). Read more...
Evidence for the Existence of Dark Matter
Mass discrepancies in galaxies and clusters, cosmic background radiation, the structure of the universe, and big bang nucleosynthesis’s impact on baryon density. Read more...
Blog (Tier 3)
The Best Mental Model for Serious Structured Learning
… is intense physical workouts. Read more...
The Worst Possible Way to Fail at Learning Math
… is to become an academic crank. Read more...
Why Math Educators Should Care About Talent Development
In math, de-prioritizing talent development leads to major issues. Read more...
Yes, you need to spin up on foundational knowledge. No, you are not an exception.
Even Ramanujan self-studied. Read more...
Active Problem-Solving is Where The Learning Happens
Comfortable fluency in consuming information is not a proxy for actual learning. Read more...
The #1 Trick for Super-Productivity
… is interleaving a wide variety of productive work that you enjoy. Read more...
Schooling vs Talent Development
Schooling and talent development are completely different things. Read more...
3 Common Areas of Confusion in Talent Development
(especially in math learning) Read more...
The Vicious Cycle of Context Overload
Why jumping the gun on complexity leads to compounding struggle. Read more...
Actively Doing is the Key to Alpha
Lots of people consume. Fewer people actively do. Even fewer people attempt challenging things. And even fewer people than that build up the foundational skills needed to succeed in doing those challenging things. Read more...
How To Get Stuff To Stick In Your Brain
Always try your best to recall it from memory. DO NOT default to looking it up. Read more...
It’s Memorization All The Way Down
At the end of the day all learning is memorization. Read more...
How to Mitigate Intellectual Body Dysmorphia
Compare the capabilities of your present self to your past self. That should make the growth obvious. Read more...
It’s Not About the Type of Motivation, It’s About the Total Amount of Motivation
Appreciation of mathematical beauty gets held up on too high a pedestal as the “correct” source of motivation in math learning. Read more...
The Future of Math Facts Practice on Math Academy
And the problem with many existing times tables practice systems. Read more...
Make the Habit Easily Repeatable
Start out with a volume of work that’s small enough that you don’t dread doing it again the next day. Read more...
Some Tips for Junior Devs
1) Learn SQL and how to use a debugger. 2) Never come up emptyhanded, even if you don’t fix the bug. Read more...
It’s Rare to Find Computation Walkthroughs in ML Learning Resources
Coding tutorials typically just say “import this function then run it,” and the math tutorials typically just say “this is the form of the model, you can fit it using the usual techniques” and leave it to the reader to figure out the rest. Read more...
Make it So Easy a Kid Can Learn It
If you can scaffold the content so well that it creates a smooth, efficient learning experience for knucklehead kids, it’s going to feel even smoother for more conscientious adults. Read more...
Get On the Right Team
You can be the most committed and capable workhorse on the planet, but if you’re on the wrong team, the only thing you’ll change is your team’s allocation of work. Read more...
Selected Blog Posts About the State of Math Education
Specific areas of friction that cause students to struggle with math. What needs to be done to remove friction from the learning process. Why friction remains so prevalent. Read more...
How To Mitigate Nonsense from Lazy/Adversarial Students
Enter grades early on, and (if pre-college) email parents early on. Read more...
How to Allocate Your Bandwidth While Searching for Your Mission
One main focus, one semi-focus, and everything else a hobby with whatever time you have left over. Read more...
Don’t Overreact to Bad Days
It can help to zoom out and look at your progress on a longer timescale. Read more...
Failure Modes in People Who Develop Math Skills but Don’t Capitalize On Them via Coding
1) Difficulty grappling with complexity when it grows so big that you can’t fit everything in your head. 2) Lack of understanding or willingness to accept practical constraints of the problem and incorporate them into the solution. 3) Getting distracted by low-ROI features/details. 4) Being unwilling to do “tedious” work. Read more...
What Math To Learn Next After Calculus
Depending on your goals, either A) methods of proof, or B) linear algebra followed by probability & statistics. Read more...
When Should Students Memorize Math Facts?
It’s helpful to loosely understand what something means before memorizing it, but this does not have to be a rigorous derivation. Read more...
“Learning” Info Without Practicing Reproducing it is Not Really Learning
It’s really just “loading” the info into temporary storage – like picking up a weight off the rack, whereas learning is increasing your ability to lift said weight. Read more...
Mistakes That Knowledgeable People Make When Teaching
1) Confusing “conceptually simple” with “notationally compact”, and 2) jumping to the most general method right away. Read more...
Love What You Do
If you don’t love it, you’ll never be able to keep up with the same volume of effective practice as someone who does have that love. You’ll never outwork them. Read more...
Go Through the Question Bank Breadth-First, not Depth-First
An easy trick to improve your retention while working through a bank of review or challenge problems like LeetCode, HackerRank, etc. Read more...
Top-down’s fine for playing around. You’ll run into walls, but don’t give up — go bottom-up to get unstuck.
A little rhyme to understand the big picture of top-down vs bottom-up learning, particularly in the context of machine learning (ML). Read more...
Just Do The F*cking Work
At the end of the day you can either waste time debating your coach on the training regimen, or you can use that time to just put your head down and do some f*cking work. Read more...
Pictures are Valuable in Math Learning, but They’re Often Overvalued
Pictures can help build mathematical intuition, but sometimes learners think they should fully visualize every single problem they solve, which actually handicaps their thinking. Math involves generalizing patterns in logically consistent ways, and the generalizations eventually go beyond what you can fully picture in your head. Read more...
The “Progress Equals Pressure” Formula
Making progress is all about putting pressure on a problem: applying the force of your skills to a specific problem area (pressure = force / area). Read more...
The Future of Proof-Based Courses on Math Academy
And why we refer to ourselves as still being “in beta.” Read more...
Why is there sometimes resistance to automaticity in education?
The need for automaticity on low-level skills is obvious to anyone with experience learning a sport or instrument. So why is there sometimes resistance in education? It makes sense if you think about what people usually find persuasive. Read more...
Competition as a Means of Collaboration
The whole idea is that you want the other person to raise the bar on competition and pass you up, so that you’re motivated to come right back and do the same to them. Read more...
Writing is a Skill that Can Be Trained
Every time you put out a post, get feedback, make improvements, and carry those improvements forward into future posts, that’s essentially a “rep” of deliberate practice. Read more...
Some Pitfalls to Watch Out For when Learning From Projects
1) Don’t use projects as a way to acquire fundamental skills. 2) Make sure the projects are guided. 3) Don’t let the projects cut too much into your foundational skill-building. Read more...
Enjoyment is a Second-Order Optimization
Fun is a supplement, not a substitute, for deliberate practice. Read more...
Critique of Article: The Problems With Deliberate Practice
The article presents two claims of deliberate practice that it argues against – but the first claim is a misattribution, and the second claim is not actually argued against. Read more...
Resolving Confusion about Deliberate Practice
Doesn’t “beyond the edge of one’s capabilities” mean that you can’t do it? How can you practice it if you can’t do it? Also, “performance-improving adjustments on every single repetition” is hard to understand in some realms of performance. For instance, does each step a runner takes involve feedback and improvement? Read more...
My Next Big Modeling Project: Behavior Coaching
Even if students are working on exactly the right things, they need to be working exactly the right way to capture the most learning from their time spent working. Read more...
True active learning means…
every individual student is actively engaged on every piece of material to be learned. Read more...
Spaced repetition is more than memorization – it’s also generalization.
And if you want to get the most out of your review, you need to engage in spaced, interleaved retrieval practice. Read more...
How “Kicking the Can Down the Road” Happens in Education
It’s the tragedy of the commons. Read more...
How to Learn Machine Learning: Top Down or Bottom Up?
It can be helpful to take a top-down approach in planning out your overarching learning goals, but the learning itself has to occur bottom-up. Read more...
Book Review: Developing Talent in Young People by Benjamin Bloom
Bloom studied the training backgrounds of 120 world-class talented individuals across 6 talent domains: piano, sculpting, swimming, tennis, math, & neurology, and what he discovered was that talent development occurs through a similar general process, no matter what talent domain. In other words, there is a “formula” for developing talent – though executing it is a lot harder than simply understanding it. Read more...
Ability is Built, Not Unlocked
Curiosity/interest motivates people to engage in deliberate practice, which is what builds ability. Read more...
The Best Description of Explicit Instruction I’ve Ever Heard
Effective explicit instruction is all about clarity, and breaking down information, and minimizing the load on working memory. Read more...
The 2 Most Common Ways that People Get Retrieval Practice Wrong
1) The information must have already been written to memory. 2) The information must be retrieved from memory, unassisted. Read more...
Why Extrinsic Motivation Matters
I think optimal motivation requires a balance of both intrinsic and extrinsic factors. Read more...
Different Students Need Different Amounts of Practice
The amount of practice should be determined on the basis of each student’s individual performance on each individual topic. Some students may end up having to do more work, but this ultimately empowers them to learn and continue learning into the future. Read more...
Overcoming the Paradox of Serious Training
Here’s a trick to feel amazingly capable and confident: periodically look back at stuff you originally found challenging months ago. Read more...
Math is Overpowered When Combined with Other Expertise but Underpowered Alone
When you’re knowledgeable/skilled enough to grapple with problems in a more directly applicable field, math gives you the superpower of being able to compress those problem representations into an abstract space where they’re easier to solve. Read more...
“Following Along” vs Learning
You haven’t learned unless you’re able to consistently reproduce the information you consumed and use it to solve problems. Read more...
The Issue with Watered-Down Math Courses
When students are not given the opportunity to learn math seriously, and are instead presented with watered-down courses and told that they’re doing a great job, they’re being set up for failure later in life when it matters most. Read more...
If You Want to Learn Math, You Can’t Shy Away from Computation
Learning math with little computation is like learning basketball with little practice on dribbling & ball handling techniques. Read more...
Silly Mistakes are Still Mistakes
… and they should be treated as such. Read more...
Why 4x8 and 6x8 Are, Perhaps Surprisingly, Some of the Hardest Multiplication Facts for Students to Remember
There’s a cognitive principle behind this: associative interference, the phenomenon that conceptually related pieces of knowledge can interfere with each other’s recall. Read more...
There is No Such Thing as Low-Effort Learning
No matter what skill is being trained, improving performance is always an effortful process. Read more...
Spaced Repetition vs Spiraling
By periodically revisiting content, a spiral curriculum periodically restores forgotten knowledge and leverages the spacing effect to slow the decay of that knowledge. Spaced repetition takes this line of thought to its fullest extent by fully optimizing the review process. Read more...
Learning vs Feeling
The strongest people lift weights heavy enough to make them feel weak. Read more...
Leveraging Cognitive Learning Strategies Requires Technology
While there is plenty of room for teachers to make better use of cognitive learning strategies in the classroom, teachers are victims of circumstance in a profession lacking effective accountability and incentive structures, and the end result is that students continue to receive mediocre educational experiences. Given a sufficient degree of accountability and incentives, there is no law of physics preventing a teacher from putting forth the work needed to deliver an optimal learning experience to a single student. However, in the absence of technology, it is impossible for a single human teacher to deliver an optimal learning experience to a classroom of many students with heterogeneous knowledge profiles, each of whom needs to work on different types of problems and receive immediate feedback on each of their attempts. This is why technology is necessary. Read more...
The Utility of Gamification in Learning
Gamification, integrating game-like elements into learning environments, proves effective in increasing student learning, engagement, and enjoyment. Read more...
Cognitive Science of Learning: The Testing Effect (Retrieval Practice)
The testing effect (or the retrieval practice effect) emphasizes that recalling information from memory, rather than repeated reading, enhances learning. It can be combined with spaced repetition to produce an even more potent learning technique known as spaced retrieval practice. Read more...
Cognitive Science of Learning: Interleaving (Mixed Practice)
Interleaving (or mixed practice) involves spreading minimal effective doses of practice across various skills, in contrast to blocked practice, which involves extensive consecutive repetition of a single skill. Blocked practice can give a false sense of mastery and fluency because it allows students to settle into a robotic rhythm of mindlessly applying one type of solution to one type of problem. Interleaving, on the other hand, creates a “desirable difficulty” that promotes vastly superior retention and generalization, making it a more effective review strategy. But despite its proven efficacy, interleaving faces resistance in classrooms due to a preference for practice that feels easier and appears to produce immediate performance gains, even if those performance gains quickly vanish afterwards and do not carry over to test performance. Read more...
Cognitive Science of Learning: Spaced Repetition (Distributed Practice)
When reviews are spaced out or distributed over multiple sessions (as opposed to being crammed or massed into a single session), memory is not only restored, but also further consolidated into long-term storage, which slows its decay. This is known as the spacing effect. A profound consequence of the spacing effect is that the more reviews are completed (with appropriate spacing), the longer the memory will be retained, and the longer one can wait until the next review is needed. This observation gives rise to a systematic method for reviewing previously-learned material called spaced repetition (or distributed practice). A repetition is a successful review at the appropriate time. Read more...
Layering: Building Structural Integrity in Knowledge
Layering is the act of continually building on top of existing knowledge – that is, continually acquiring new knowledge that exercises prerequisite or component knowledge. This causes existing knowledge to become more ingrained, organized, and deeply understood, thereby increasing the structural integrity of a student’s knowledge base and making it easier to assimilate new knowledge. Read more...
Cognitive Science of Learning: Minimizing Associative Interference
Associative interference occurs when related knowledge interferes with recall. It is more likely to occur when highly related pieces of knowledge are learned simultaneously or in close succession. However, the effects of interference can be mitigated by teaching dissimilar concepts simultaneously and spacing out related pieces of knowledge over time. Read more...
Cognitive Science of Learning: Developing Automaticity
Automaticity is the ability to perform low-level skills without conscious effort. Analogous to a basketball player effortlessly dribbling while strategizing, automaticity allows individuals to avoid spending limited cognitive resources on low-level tasks and instead devote those cognitive resources to higher-order reasoning. In this way, automaticity is the gateway to expertise, creativity, and general academic success. However, insufficient automaticity, particularly in basic skills, inflates the cognitive load of tasks, making it exceedingly difficult for students to learn and perform. Read more...
Cognitive Science of Learning: Minimizing Cognitive Load
Different students have different working memory capacities. When the cognitive load of a learning task exceeds a student’s working memory capacity, the student experiences cognitive overload and is not able to complete the task. Read more...
A Brief History of Mastery Learning
Mastery learning is a strategy in which students demonstrate proficiency on prerequisites before advancing. While even loose approximations of mastery learning have been shown to produce massive gains in student learning, mastery learning faces limited adoption due to clashing with traditional teaching methods and placing increased demands on educators. True mastery learning at a fully granular level requires fully individualized instruction and is only attainable through one-on-one tutoring. Read more...
The Neuroscience of Active Learning and Automaticity
Active learning leads to more neural activation than passive learning. Automaticity involves developing strategic neural connections that reduce the amount of effort that the brain has to expend to activate patterns of neurons. Read more...
Active Learning: If You’re Active Half the Time, That’s Still Not Enough
During practice, the elite skaters were over 6 times more active than passive, while non-competitive skaters were nearly as passive as they were active. Read more...
What Counts as Active Learning?
True active learning requires every individual student to be actively engaged on every piece of the material to be learned. Read more...
The Double-Edged Nature of Hierarchical Knowledge
It’s easier to run into roadblocks, but also easier to maintain what you’ve learned. Read more...
You Know it’s Edutainment When…
Passive consumption. Lack of depth. Lack of rigorous assessments. Failing upwards. Lack of skill development. Read more...
Recommended Language, Tools, Path, and Curriculum for Teaching Kids to Code
I’d start off with some introductory course that covers the very basics of coding in some language that is used by many professional programmers but where the syntax reads almost like plain English and lower-level details like memory management are abstracted away. Then, I’d jump right into building board games and strategic game-playing agents (so a human can play against the computer), starting with simple games (e.g. tic-tac-toe) and working upwards from there (maybe connect 4 next, then checkers, and so on). Read more...
Tips for Learning Math Effectively
Solving problems, building on top of what you’ve learned, reviewing what you’ve learned, and quality, quantity, and spacing of practice. Read more...
Myths and Realities about Educational Acceleration
Acceleration does not lead to adverse psychological consequences in capable students; rather, whether a student is ready for advanced mathematics depends solely on whether they have mastered the prerequisites. Acceleration does not imply shallowness of learning; rather, students undergoing acceleration generally learn – in a shorter time – as much as they would otherwise in a non-accelerated environment over a proportionally longer period of time. Accelerated students do not run out of courses to take and are often able to place out of college math courses even beyond what is tested on placement exams. Lastly, for students who have the potential to capitalize on it, acceleration is the greatest educational life hack: the resulting skills and opportunities can rocket students into some of the most interesting, meaningful, and lucrative careers, and the early start can lead to greater career success. Read more...
Effective Learning Requires Intense Effort
Effortful processes like testing, repetition, and computation are essential parts of effective learning, and competition is often helpful. Read more...
Effective Learning Does Not Emulate the Professional Workplace
The most effective learning techniques require substantial cognitive effort from students and typically do not emulate what experts do in the professional workplace. Direct instruction is necessary to maximize student learning, whereas unguided instruction and group projects are typically very inefficient. Read more...
The Story of the Science of Learning
In terms of improving educational outcomes, science is not where the bottleneck is. The bottleneck is in practice. The science of learning has advanced significantly over the past century, yet the practice of education has barely changed. Read more...
The Tragedy of the Commons in Education
Why it’s common for students to pass courses despite severely lacking knowledge of the content. Read more...
How I Won a Heat Capacitor Competition Without a Heat Capacitor
Won first place in a state-level competition by finding and exploiting a loophole in the points scoring logic. Read more...
According to Feynman himself, his classes were a failure for 90% of his students.
While some may view Feynman-style pedagogy as supporting inclusive learning for all students across varying levels of ability, Feynman himself acknowledged that his methods only worked for the top 10% of his students. Read more...
Business Lessons from Science Fair
The most important things I learned from competing in science fairs had nothing to do with physics or even academics. My main takeaways were actually related to business – in particular, sales and marketing. Read more...
Why I Don’t Worship at the Altar of Neural Nets
In order to justify using a more complex model, the increase in performance has to be worth the cost of integrating and maintaining the complexity. Read more...
Selecting a Good Problem to Work On
Good problem = intersection between your own interests/talents, the realm of what’s feasible, and the desires of the external world. Read more...
Tips for Developing Valuable Models
Stuff you don’t find in math textbooks. Read more...
The Counterintuitive Nature of Effective Learning Strategies
Effective learning strategies sometimes go against our human instincts about conversation. Read more...
Talent Development
(In Progress) Advice on Upskilling
You’re Not Lazy, You Just Lack a Habit • Don’t have a passion? Go create one. • Make the Habit Easily Repeatable • Don’t Overreact to Bad Days • Aim for Virtuous Cycles • The Importance of Hardcore Skills • Fortify Your F*cking Fundamentals • Why Train? • The Magic You’re Looking For is in the Full-Assed Effort You’re Avoiding • At some point Doing the Hard Thing becomes Easier than Making the Hard Thing Easier • How to Cultivate Discipline • Keep Your Hands On The Boulder Read more...
Learning Higher-Grade Math Ahead of Time is the Greatest Educational/Career Life Hack
Higher-grade math unlocks specialized fields that students normally couldn’t access until much later – and on average, the faster you accelerate your learning, the sooner you get your career started, and the more you accomplish over the course of your career. Read more...
Fortify Your F*cking Fundamentals
Skating around the rink will get you to a decent level of comfort in your basic skating skills, but being able to land jumps and spins will force a whole new level of robustness and fault-tolerance in those underlying skills. The same applies to knowledge in general. Read more...
The Best Mental Model for Serious Structured Learning
… is intense physical workouts. Read more...
You Can Effectively Turn Long-Term Memory Into An Extension of Working Memory
The way to do this is to develop automaticity on your lower-level skills. Read more...
The Worst Possible Way to Fail at Learning Math
… is to become an academic crank. Read more...
Why Math Educators Should Care About Talent Development
In math, de-prioritizing talent development leads to major issues. Read more...
Introduction to the Expertise Reversal Effect
Beginners (i.e., students) learn most effectively through direct instruction. Read more...
Yes, you need to spin up on foundational knowledge. No, you are not an exception.
Even Ramanujan self-studied. Read more...
Failure Modes in the Talent Development Process
The permastudent, the wannabe, and the dilettante. Read more...
Active Problem-Solving is Where The Learning Happens
Comfortable fluency in consuming information is not a proxy for actual learning. Read more...
Schooling vs Talent Development
Schooling and talent development are completely different things. Read more...
How To Get a Full Time Software Job During College (5-Step Roadmap)
I worked full time in data science during my last 2 years of undergrad and I’m pretty sure the process to pull this off is reproducible. Read more...
Prereq Yo’ Self Before You Wreck Yo’ Self
If you hammer prerequisite concepts/skills into your long-term memory, get it really solid and easy to retrieve, then you can lessen the load on your working memory, keep it below capacity, avoid getting “broken,” and keep up with the game. Read more...
The Vicious Cycle of Context Overload
Why jumping the gun on complexity leads to compounding struggle. Read more...
Actively Doing is the Key to Alpha
Lots of people consume. Fewer people actively do. Even fewer people attempt challenging things. And even fewer people than that build up the foundational skills needed to succeed in doing those challenging things. Read more...
The Magic You’re Looking For is in the Full-Assed Effort You’re Avoiding
When someone fails to make decent progress towards their learning or fitness goals and cites lack of time as the issue, they’re often wrong. Read more...
Top 3 Skills
Math, coding, communication. Read more...
How I Would Go About Learning an Arbitrary Subject Where No Full-Fledged Adaptive Learning System is Available
I’m using an LLM to learn biology. My overall conclusion is that IF you could learn successfully, long-term, by self-studying textbooks on your own, and the only thing keeping you from learning a new subject is a slight lack of time, THEN you can probably use LLM prompting to speed up that process a bit, which can help you pull the trigger on learning some stuff you previously didn’t have time for. BUT the vast, vast majority of people are going to need a full-fledged learning system. And even for that miniscule portion of people for whom the “IF” applies… whatever the efficiency gain of LLM prompting over standard textbooks, there’s an even bigger efficiency gain of full-fledged learning system over LLM prompting. Read more...
Competition Math is NOT an All-Encompassing Holy Grail of Math Learning or General Problem Solving
Skill development all comes down to building domain-specific chunks in long-term memory. The way you increase your ability to make mental leaps is not actually by jumping farther, but rather, by building bridges that reduce the distance you need to jump. Read more...
The Pursuit of Real Life Superhero Training
I just want to build a thermodynamic machine that makes people insanely skilled as efficiently as possible. Read more...
At some point doing the hard thing becomes easier than making the hard thing easier.
And that’s when you have to muster up the willpower to overcome whatever friction is left over. Read more...
How to Mitigate Intellectual Body Dysmorphia
Compare the capabilities of your present self to your past self. That should make the growth obvious. Read more...
It’s Not About the Type of Motivation, It’s About the Total Amount of Motivation
Appreciation of mathematical beauty gets held up on too high a pedestal as the “correct” source of motivation in math learning. Read more...
If You’re Asking Someone to Be Your Mentor then You’re Doing it Wrong
It should look less like them helping you and more like you helping them. Read more...
Make the Habit Easily Repeatable
Start out with a volume of work that’s small enough that you don’t dread doing it again the next day. Read more...
Get On the Right Team
You can be the most committed and capable workhorse on the planet, but if you’re on the wrong team, the only thing you’ll change is your team’s allocation of work. Read more...
Math is a Well-Defined Body of Knowledge
At the end of the day, whether or not they know math comes down to whether or not they can apply techniques within that well-defined body of knowledge to solve problems within that well-defined body of knowledge. Read more...
The Necessity of Grinding Through Concrete Examples Before Jumping Up a Level of Abstraction
If you go directly to the most abstract ideas then you’re basically like a kid who reads a book of famous quotes about life and thinks they understand everything about life by way of those quotes. Read more...
Learning Math is Like Climbing a Ladder
… an infinitely tall ladder where the rungs get spaced further and further apart the higher you climb. Read more...
The Key to Learning Fast
… is reducing friction in the learning process. Read more...
How to Allocate Your Bandwidth While Searching for Your Mission
One main focus, one semi-focus, and everything else a hobby with whatever time you have left over. Read more...
How to Cultivate Discipline
Tear down the unproductive habit and build up a counter-habit whose gravity eventually becomes strong enough to completely overtake the original habit. Read more...
Don’t Overreact to Bad Days
It can help to zoom out and look at your progress on a longer timescale. Read more...
Transformation Is Discomforting
What you want is a continual cycle of strain and adaptation. Read more...
Love What You Do
If you don’t love it, you’ll never be able to keep up with the same volume of effective practice as someone who does have that love. You’ll never outwork them. Read more...
Complete Individualization: an Often-Forgotten yet Critical Component of True Deliberate Practice
There are many studies demonstrating a benefit of some component of deliberate practice, but these studies often get mislabeled or misinterpreted as demonstrating the full benefit of true deliberate practice. The field of education is particularly susceptible to this issue because it is impossible for a teacher with a classroom of students to provide a true deliberate practice experience without assistive technology that perfectly emulates the one-on-one pedagogical decisions that an expert tutor would make for each individual student. Read more...
Top-down’s fine for playing around. You’ll run into walls, but don’t give up — go bottom-up to get unstuck.
A little rhyme to understand the big picture of top-down vs bottom-up learning, particularly in the context of machine learning (ML). Read more...
Just Do The F*cking Work
At the end of the day you can either waste time debating your coach on the training regimen, or you can use that time to just put your head down and do some f*cking work. Read more...
The “Progress Equals Pressure” Formula
Making progress is all about putting pressure on a problem: applying the force of your skills to a specific problem area (pressure = force / area). Read more...
Five Steps to Becoming a Fully-Fledged Quantitative Software Engineer
Once you get past steps 1-3, it’s hard to find scaffolding. You can’t just enroll in a course or pick up a textbook. The scaffolding comes from finding a mentor on a mission that you identify with and are well-suited to contribute to. And it can take a lot of searching to find that person and problem area that’s the right fit. Read more...
Writing is a Skill that Can Be Trained
Every time you put out a post, get feedback, make improvements, and carry those improvements forward into future posts, that’s essentially a “rep” of deliberate practice. Read more...
Some Pitfalls to Watch Out For when Learning From Projects
1) Don’t use projects as a way to acquire fundamental skills. 2) Make sure the projects are guided. 3) Don’t let the projects cut too much into your foundational skill-building. Read more...
You Are NOT Lazy, You Just Lack a Habit
The habit is a psychological force field that protects you from all sorts of negative feelings that try to dissuade you from training. Read more...
The “Alien-Level Skills” Hack
You get to provide value that nobody else can, and you get recognized for it. Read more...
Enjoyment is a Second-Order Optimization
Fun is a supplement, not a substitute, for deliberate practice. Read more...
Critique of Article: The Problems With Deliberate Practice
The article presents two claims of deliberate practice that it argues against – but the first claim is a misattribution, and the second claim is not actually argued against. Read more...
Resolving Confusion about Deliberate Practice
Doesn’t “beyond the edge of one’s capabilities” mean that you can’t do it? How can you practice it if you can’t do it? Also, “performance-improving adjustments on every single repetition” is hard to understand in some realms of performance. For instance, does each step a runner takes involve feedback and improvement? Read more...
How to get from high school math to cutting-edge ML/AI: a detailed 4-stage roadmap with links to the best learning resources that I’m aware of.
1) Foundational math. 2) Classical machine learning. 3) Deep learning. 4) Cutting-edge machine learning. Read more...
Book Review: Developing Talent in Young People by Benjamin Bloom
Bloom studied the training backgrounds of 120 world-class talented individuals across 6 talent domains: piano, sculpting, swimming, tennis, math, & neurology, and what he discovered was that talent development occurs through a similar general process, no matter what talent domain. In other words, there is a “formula” for developing talent – though executing it is a lot harder than simply understanding it. Read more...
Ability is Built, Not Unlocked
Curiosity/interest motivates people to engage in deliberate practice, which is what builds ability. Read more...
Why Extrinsic Motivation Matters
I think optimal motivation requires a balance of both intrinsic and extrinsic factors. Read more...
What’s the Best Way to Teach Math: Explicit Instruction or Less Guided Learning?
Nobody who knows the science of learning is actually debating this. Read more...
Overcoming the Paradox of Serious Training
Here’s a trick to feel amazingly capable and confident: periodically look back at stuff you originally found challenging months ago. Read more...
The Pedagogically Optimal Way to Learn Math
The underlying principle that it all boils down to is deliberate practice. Read more...
Who Needs Worked Examples? You, Eventually.
Math gets hard for different students at different levels. If you don’t have worked examples to help carry you through once math becomes hard for you, then every problem basically blows up into a “research project” for you. Sometimes people advocate for unguided struggle as a way to improve general problem-solving ability, but this idea lacks empirical support. Worked examples won’t prevent you from developing deep understanding (actually, it’s the opposite: worked examples can help you quickly layer on more skills, which forces a structural integrity in the lower levels of your knowledge). Even if you decide against using worked examples for now, continually re-evaluate to make sure you’re getting enough productive training volume. Read more...
Levels of Mathematics
Research mathematicians are like professional athletes. Read more...
The Most Superior Form of Training and the Most Hard-Hitting 2 Sentences in All of Talent Development Research
“…[D]eliberate practice requires effort and is not inherently enjoyable. Individuals are motivated to practice because practice improves performance.” Read more...
How Bloom’s Taxonomy Gets Misinterpreted
Many educators think that the makeup of every year in a student’s education should be balanced the same way across Bloom’s taxonomy, whereas Bloom’s 3-stage talent development process suggests that the time allocation should change drastically as a student progresses through their education. Read more...
Silly Mistakes are Still Mistakes
… and they should be treated as such. Read more...
What People Think Maximum-Efficiency Learning Should Feel Like, vs What it Actually Feels Like
When you’re developing skills at peak efficiency, you are maximizing the difficulty of your training tasks subject to the constraint that you end up successfully overcoming those difficulties in a timely manner. Read more...
Bloom’s 3 Stages of Talent Development
First, fun and exciting playtime. Then, intense and strenuous skill development. Finally, developing one’s individual style while pushing the boundaries of the field. Read more...
Talent Development vs Traditional Schooling
Talent development is not only different from schooling, but in many cases completely orthogonal to schooling. Read more...
Bloom’s Two-Sigma Problem
The average tutored student performed better than 98% of students in the traditional class. Read more...
Coding
How To Get a Full Time Software Job During College (5-Step Roadmap)
I worked full time in data science during my last 2 years of undergrad and I’m pretty sure the process to pull this off is reproducible. Read more...
On Writing Good Code
It’s kind of amusing how some (novice) devs will boast/revel at how many lines of code they wrote while simultaneously cramming each line full with as much complexity as they can hold in working memory. Read more...
Some Tips for Junior Devs
1) Learn SQL and how to use a debugger. 2) Never come up emptyhanded, even if you don’t fix the bug. Read more...
Failure Modes in People Who Develop Math Skills but Don’t Capitalize On Them via Coding
1) Difficulty grappling with complexity when it grows so big that you can’t fit everything in your head. 2) Lack of understanding or willingness to accept practical constraints of the problem and incorporate them into the solution. 3) Getting distracted by low-ROI features/details. 4) Being unwilling to do “tedious” work. Read more...
How to get from high school math to cutting-edge ML/AI: a detailed 4-stage roadmap with links to the best learning resources that I’m aware of.
1) Foundational math. 2) Classical machine learning. 3) Deep learning. 4) Cutting-edge machine learning. Read more...
How do you apply math to CS when so many software engineers say that there is not that much math in coding?
Write code that makes complicated decisions, often involving some kind of inference. Read more...
Recommended Language, Tools, Path, and Curriculum for Teaching Kids to Code
I’d start off with some introductory course that covers the very basics of coding in some language that is used by many professional programmers but where the syntax reads almost like plain English and lower-level details like memory management are abstracted away. Then, I’d jump right into building board games and strategic game-playing agents (so a human can play against the computer), starting with simple games (e.g. tic-tac-toe) and working upwards from there (maybe connect 4 next, then checkers, and so on). Read more...
The Story of Math Academy’s Eurisko Sequence: the Most Advanced High School Math/CS Sequence in the USA
During its operation from 2020 to 2023, Eurisko was the most advanced high school math/CS sequence in the USA. It culminated in high school students doing masters/PhD-level coursework (reproducing academic research papers in artificial intelligence, building everything from scratch in Python). Read more...
Why I Don’t Worship at the Altar of Neural Nets
In order to justify using a more complex model, the increase in performance has to be worth the cost of integrating and maintaining the complexity. Read more...
Quants vs Systems Coders
Two subtypes of coders that I watched students grow into. Read more...
From Procedures to Objects
An aha moment with object-oriented programming. Read more...
Reimplementing Blondie24: Convolutional Version
Using convolutional layers to create an even better checkers player. Read more...
Reimplementing Blondie24
Extending Fogel’s tic-tac-toe player to the game of checkers. Read more...
Reimplementing Fogel’s Tic-Tac-Toe Paper
Reimplementing the paper that laid the groundwork for Blondie24. Read more...
Introduction to Blondie24 and Neuroevolution
A method for training neural networks that works even when training feedback is sparse. Read more...
Reduced Search Depth and Heuristic Evaluation for Connect Four
Combining game-specific human intelligence (heuristics) and generalizable artificial intelligence (minimax on a game tree) Read more...
Minimax Strategy
Repeatedly choosing the action with the best worst-case scenario. Read more...
Canonical and Reduced Game Trees for Tic-Tac-Toe
Building data structures that represent all the possible outcomes of a game. Read more...
Backpropagation
A convenient technique for computing gradients in neural networks. Read more...
Introduction to Neural Network Regressors
The deeper or more “hierarchical” a computational graph is, the more complex the model that it represents. Read more...
Decision Trees
We can algorithmically build classifiers that use a sequence of nested “if-then” decision rules. Read more...
Dijkstra’s Algorithm for Distance and Shortest Paths in Weighted Graphs
Computing spatial relationships between nodes when edges no longer represent unit distances. Read more...
Distance and Shortest Paths in Unweighted Graphs
Using traversals to understand spatial relationships between nodes in graphs. Read more...
Breadth-First and Depth-First Traversals
Graphs show up all the time in computer science, so it’s important to know how to work with them. Read more...
Naive Bayes
A simple classification algorithm grounded in Bayesian probability. Read more...
K-Nearest Neighbors
One of the simplest classifiers. Read more...
Multiple Regression and Interaction Terms
In many real-life situations, there is more than one input variable that controls the output variable. Read more...
Regression via Gradient Descent
Gradient descent can help us avoid pitfalls that occur when fitting nonlinear models using the pseudoinverse. Read more...
Overfitting, Underfitting, Cross-Validation, and the Bias-Variance Tradeoff
Just because model appears to match closely with points in the data set, does not necessarily mean it is a good model. Read more...
Power, Exponential, and Logistic Regression via Pseudoinverse
Transforming nonlinear functions so that we can fit them using the pseudoinverse. Read more...
Regressing a Linear Combination of Nonlinear Functions via Pseudoinverse
Exploring the most general class of functions that can be fit using the pseudoinverse. Read more...
Linear, Polynomial, and Multiple Linear Regression via Pseudoinverse
Using matrix algebra to fit simple functions to data sets. Read more...
Simplex Method
A technique for maximizing linear expressions subject to linear constraints. Read more...
Hash Tables
Under the hood, dictionaries are hash tables. Read more...
Hodgkin-Huxley Model of Action Potentials in Neurons
Implementing a differential equations model that won the Nobel prize. Read more...
SIR Model For the Spread of Disease
A simple differential equations model that we can plot using multivariable Euler estimation. Read more...
Euler Estimation
Arrays can be used to implement more than just matrices. We can also implement other mathematical procedures like Euler estimation. Read more...
Tic-Tac-Toe and Connect Four
One of the best ways to get practice with object-oriented programming is implementing games. Read more...
K-Means Clustering
Guess some initial clusters in the data, and then repeatedly update the guesses to make the clusters more cohesive. Read more...
Reduced Row Echelon Form and Applications to Matrix Arithmetic
You can use the RREF algorithm to compute determinants much faster than with the recursive cofactor expansion method. Read more...
Basic Matrix Arithmetic
We can use arrays to implement matrices and their associated mathematical operations. Read more...
Merge Sort and Quicksort
Merge sort and quicksort are generally faster than selection, bubble, and insertion sort. And unlike counting sort, they are not susceptible to blowup in the amount of memory required. Read more...
Selection, Bubble, Insertion, and Counting Sort
Some of the simplest methods for sorting items in arrays. Read more...
Multivariable Gradient Descent
Just like single-variable gradient descent, except that we replace the derivative with the gradient vector. Read more...
Single-Variable Gradient Descent
We take an initial guess as to what the minimum is, and then repeatedly use the gradient to nudge that guess further and further “downhill” into an actual minimum. Read more...
Estimating Roots via Bisection Search and Newton-Raphson Method
Bisection search involves repeatedly moving one bound halfway to the other. The Newton-Raphson method involves repeatedly moving our guess to the root of the tangent line. Read more...
Solving Magic Squares via Backtracking
Backtracking can drastically cut down the number of possibilities that must be checked during brute force. Read more...
Brute Force Search with Linear-Encoding Cryptography
Brute force search involves trying every single possibility. Read more...
Cartesian Product
Implementing the Cartesian product provides good practice working with arrays. Read more...
Roulette Wheel Selection
How to sample from a discrete probability distribution. Read more...
Simulating Coin Flips
Estimating probabilities by simulating a large number of random experiments. Read more...
Recursive Sequences
Sequences where each term is a function of the previous terms. Read more...
Converting Between Binary, Decimal, and Hexadecimal
There are other number systems that use more or fewer than ten characters. Read more...
Some Short Introductory Coding Exercises
It’s assumed that you’ve had some basic exposure to programming. Read more...
CheckMySteps: A Web App to Help Students Fix their Algebraic Mistakes
A prototype web app to automatically assist students in self-correcting small errors and minor misconceptions. Read more...
Solving Tower of Hanoi with General Problem Solver
A walkthrough of solving Tower of Hanoi using the approach of one of the earliest AI systems. Read more...
Cutting Through the Hype of AI
Media outlets often make the mistake of anthropomorphizing or attributing human-like characteristics to computer programs. Read more...
The Third Wave of AI: Computation Power and Neural Networks
As computation power increased, neural networks began to take center stage in AI. Read more...
The Second Wave of AI: Expert Systems
Expert systems stored “if-then” rules derived from the knowledge of experts. Read more...
The First Wave of AI: Reasoning as Search
Framing reasoning as searching through a maze of actions for a sequence that achieves the desired end goal. Read more...
What is AI?
Turing test, games, hype, narrow vs general AI. Read more...
Introductory Python: Functions
Rather than duplicating such code each time we want to use it, it is more efficient to store the code in a function. Read more...
Introductory Python: If, While, and For
We often wish to tell the computer instructions involving the words “if,” “while,” and “for.” Read more...
Introductory Python: Lists, Dictionaries, and Arrays
We can store many related pieces of data within a single variable called a data structure. Read more...
Introductory Python: Strings, Ints, Floats, and Booleans
We can store and manipulate data in the form of variables. Read more...
Cognitive Science
Retrival Practice is F*cking Obvious
In the science of learning, there is absolutely no debate: practice techniques that center around retrieving information directly from one’s brain produce superior learning outcomes compared to techniques that involve re-ingesting information from an external source. Read more...
You Can Effectively Turn Long-Term Memory Into An Extension of Working Memory
The way to do this is to develop automaticity on your lower-level skills. Read more...
Introduction to the Expertise Reversal Effect
Beginners (i.e., students) learn most effectively through direct instruction. Read more...
Active Problem-Solving is Where The Learning Happens
Comfortable fluency in consuming information is not a proxy for actual learning. Read more...
Competition Math is NOT an All-Encompassing Holy Grail of Math Learning or General Problem Solving
Skill development all comes down to building domain-specific chunks in long-term memory. The way you increase your ability to make mental leaps is not actually by jumping farther, but rather, by building bridges that reduce the distance you need to jump. Read more...
The Pursuit of Real Life Superhero Training
I just want to build a thermodynamic machine that makes people insanely skilled as efficiently as possible. Read more...
How To Get Stuff To Stick In Your Brain
Always try your best to recall it from memory. DO NOT default to looking it up. Read more...
It’s Memorization All The Way Down
At the end of the day all learning is memorization. Read more...
Two of the Biggest Myths in Education
Myth 1: Understanding amounts to something other than memory. Myth 2: Sudents can perform high-level skills without mastering low-level component skills. Read more...
Selected Blog Posts About the State of Math Education
Specific areas of friction that cause students to struggle with math. What needs to be done to remove friction from the learning process. Why friction remains so prevalent. Read more...
When Should Students Memorize Math Facts?
It’s helpful to loosely understand what something means before memorizing it, but this does not have to be a rigorous derivation. Read more...
“Learning” Info Without Practicing Reproducing it is Not Really Learning
It’s really just “loading” the info into temporary storage – like picking up a weight off the rack, whereas learning is increasing your ability to lift said weight. Read more...
Complete Individualization: an Often-Forgotten yet Critical Component of True Deliberate Practice
There are many studies demonstrating a benefit of some component of deliberate practice, but these studies often get mislabeled or misinterpreted as demonstrating the full benefit of true deliberate practice. The field of education is particularly susceptible to this issue because it is impossible for a teacher with a classroom of students to provide a true deliberate practice experience without assistive technology that perfectly emulates the one-on-one pedagogical decisions that an expert tutor would make for each individual student. Read more...
Go Through the Question Bank Breadth-First, not Depth-First
An easy trick to improve your retention while working through a bank of review or challenge problems like LeetCode, HackerRank, etc. Read more...
Spaced repetition is so similar to weight training that it might as well be called “wait” training.
The fuzzier that memory, the harder it is to lift. The wait creates the weight. Read more...
One of the Most Amusing Errors in Teaching
… is asking students to perform activities that leverage a non-existent knowledge base. Read more...
Why is there sometimes resistance to automaticity in education?
The need for automaticity on low-level skills is obvious to anyone with experience learning a sport or instrument. So why is there sometimes resistance in education? It makes sense if you think about what people usually find persuasive. Read more...
Why I Recommend Students NOT Take Notes
If you try to keep information close by taking great notes that you can reference all the time… that just PREVENTS you from truly retaining it. Read more...
A White Pill on Cognitive Differences
It’s a hard truth that some people have more advantageous cognitive differences than others – e.g., higher working memory capacity, higher generalization ability, slower forgetting rate. However, there are two sources of hope: 1) automaticity can effectively turn your long-term memory into an extension of your working memory, and 2) many sources of friction in the learning process can be not only remedied but also exploited to increase learning speed beyond the status quo. Read more...
Spaced repetition is more than memorization – it’s also generalization.
And if you want to get the most out of your review, you need to engage in spaced, interleaved retrieval practice. Read more...
Fast, Correct Answers Do Matter in Mathematics
You gotta develop automaticity on low-level skills in order to free up mental resources for higher-level thinking! Read more...
The Most Effective Way to Motivate Students to Learn Math
… is to not overwhelm them. In my experience, students naturally enjoy math when it doesn’t feel overwhelmingly difficult to learn. Read more...
The 2 Most Common Ways that People Get Retrieval Practice Wrong
1) The information must have already been written to memory. 2) The information must be retrieved from memory, unassisted. Read more...
When should you do math in your head vs writing it out on paper?
There is an asymmetric tradeoff between 1) blowing your working memory capacity and leaving yourself unable to make progress, versus 2) wasting a couple extra seconds writing down a bit more work than you need to. When in doubt, write it out. Read more...
“Following Along” vs Learning
You haven’t learned unless you’re able to consistently reproduce the information you consumed and use it to solve problems. Read more...
The Pedagogically Optimal Way to Learn Math
The underlying principle that it all boils down to is deliberate practice. Read more...
What is learning, at a physical level in the brain?
Long-term learning is represented by the creation of strategic electrical wiring between neurons. Read more...
Higher Math Textbooks and Classes are Typically Not Aligned with the Cognitive Science of Learning
Research indicates the best way to improve your problem-solving ability in any domain is simply by acquiring more foundational skills in that domain. The way you increase your ability to make mental leaps is not actually by jumping farther, but rather, by building bridges that reduce the distance you need to jump. Yet, higher math textbooks & courses seem to focus on trying to train jumping distance instead of bridge-building. Read more...
Individual Variation in Working Memory Capacity (WMC): a First Step Down the Research Rabbit Hole
There are many, many studies that measure variation in WMC vs variation in other metrics. Read more...
The Problem with “Think Really Hard, Struggle for a While, Eventually Solve it or Look Up The Answer” Problems
Challenge problems are not a good use of time until you’ve developed the foundational skills that are necessary to grapple with these problems in a productive and timely fashion. Read more...
The Greatest Breakthrough in the Science of Education Over the Last Century
If you understand the interplay between working memory and long-term memory, then then you can actually derive – from first principles – the methods of effective teaching. Read more...
Paper Idea: A Theory of Optimal Learning Efficiency in Hierarchical Knowledge Structures
An idea for a paper that I don’t currently have the bandwidth to write. Read more...
Review Should Feel Challenging
It’s the act of successfully retrieving fuzzy memory, not clear memory, that extends the memory duration. Read more...
The Vicious Cycle of Forgetting
To transfer information into long-term memory, you need to practice retrieving it without assistance. Read more...
Why 4x8 and 6x8 Are, Perhaps Surprisingly, Some of the Hardest Multiplication Facts for Students to Remember
There’s a cognitive principle behind this: associative interference, the phenomenon that conceptually related pieces of knowledge can interfere with each other’s recall. Read more...
The Goal of Active Learning is NOT to Increase Cognitive Load
It’s actually the opposite – to get students actively retrieving information from memory, while minimizing their cognitive load. Read more...
Which Cognitive Psychology Findings are Solid, That Can Be Used to Help Students Learn Better?
There are numerous cognitive learning strategies that 1) can be used to massively improve learning, 2) have been reproduced so many times they might as well be laws of physics, and 3) connect all the way down to the mechanics of what’s going on in the brain. Read more...
Spaced Repetition vs Spiraling
By periodically revisiting content, a spiral curriculum periodically restores forgotten knowledge and leverages the spacing effect to slow the decay of that knowledge. Spaced repetition takes this line of thought to its fullest extent by fully optimizing the review process. Read more...
Leveraging Cognitive Learning Strategies Requires Technology
While there is plenty of room for teachers to make better use of cognitive learning strategies in the classroom, teachers are victims of circumstance in a profession lacking effective accountability and incentive structures, and the end result is that students continue to receive mediocre educational experiences. Given a sufficient degree of accountability and incentives, there is no law of physics preventing a teacher from putting forth the work needed to deliver an optimal learning experience to a single student. However, in the absence of technology, it is impossible for a single human teacher to deliver an optimal learning experience to a classroom of many students with heterogeneous knowledge profiles, each of whom needs to work on different types of problems and receive immediate feedback on each of their attempts. This is why technology is necessary. Read more...
Cognitive Science of Learning: The Testing Effect (Retrieval Practice)
The testing effect (or the retrieval practice effect) emphasizes that recalling information from memory, rather than repeated reading, enhances learning. It can be combined with spaced repetition to produce an even more potent learning technique known as spaced retrieval practice. Read more...
Cognitive Science of Learning: Interleaving (Mixed Practice)
Interleaving (or mixed practice) involves spreading minimal effective doses of practice across various skills, in contrast to blocked practice, which involves extensive consecutive repetition of a single skill. Blocked practice can give a false sense of mastery and fluency because it allows students to settle into a robotic rhythm of mindlessly applying one type of solution to one type of problem. Interleaving, on the other hand, creates a “desirable difficulty” that promotes vastly superior retention and generalization, making it a more effective review strategy. But despite its proven efficacy, interleaving faces resistance in classrooms due to a preference for practice that feels easier and appears to produce immediate performance gains, even if those performance gains quickly vanish afterwards and do not carry over to test performance. Read more...
Cognitive Science of Learning: Spaced Repetition (Distributed Practice)
When reviews are spaced out or distributed over multiple sessions (as opposed to being crammed or massed into a single session), memory is not only restored, but also further consolidated into long-term storage, which slows its decay. This is known as the spacing effect. A profound consequence of the spacing effect is that the more reviews are completed (with appropriate spacing), the longer the memory will be retained, and the longer one can wait until the next review is needed. This observation gives rise to a systematic method for reviewing previously-learned material called spaced repetition (or distributed practice). A repetition is a successful review at the appropriate time. Read more...
Layering: Building Structural Integrity in Knowledge
Layering is the act of continually building on top of existing knowledge – that is, continually acquiring new knowledge that exercises prerequisite or component knowledge. This causes existing knowledge to become more ingrained, organized, and deeply understood, thereby increasing the structural integrity of a student’s knowledge base and making it easier to assimilate new knowledge. Read more...
Cognitive Science of Learning: Minimizing Associative Interference
Associative interference occurs when related knowledge interferes with recall. It is more likely to occur when highly related pieces of knowledge are learned simultaneously or in close succession. However, the effects of interference can be mitigated by teaching dissimilar concepts simultaneously and spacing out related pieces of knowledge over time. Read more...
Cognitive Science of Learning: Developing Automaticity
Automaticity is the ability to perform low-level skills without conscious effort. Analogous to a basketball player effortlessly dribbling while strategizing, automaticity allows individuals to avoid spending limited cognitive resources on low-level tasks and instead devote those cognitive resources to higher-order reasoning. In this way, automaticity is the gateway to expertise, creativity, and general academic success. However, insufficient automaticity, particularly in basic skills, inflates the cognitive load of tasks, making it exceedingly difficult for students to learn and perform. Read more...
Cognitive Science of Learning: Minimizing Cognitive Load
Different students have different working memory capacities. When the cognitive load of a learning task exceeds a student’s working memory capacity, the student experiences cognitive overload and is not able to complete the task. Read more...
The Neuroscience of Active Learning and Automaticity
Active learning leads to more neural activation than passive learning. Automaticity involves developing strategic neural connections that reduce the amount of effort that the brain has to expend to activate patterns of neurons. Read more...
Myths and Realities about Educational Acceleration
Acceleration does not lead to adverse psychological consequences in capable students; rather, whether a student is ready for advanced mathematics depends solely on whether they have mastered the prerequisites. Acceleration does not imply shallowness of learning; rather, students undergoing acceleration generally learn – in a shorter time – as much as they would otherwise in a non-accelerated environment over a proportionally longer period of time. Accelerated students do not run out of courses to take and are often able to place out of college math courses even beyond what is tested on placement exams. Lastly, for students who have the potential to capitalize on it, acceleration is the greatest educational life hack: the resulting skills and opportunities can rocket students into some of the most interesting, meaningful, and lucrative careers, and the early start can lead to greater career success. Read more...
Effective Learning Requires Intense Effort
Effortful processes like testing, repetition, and computation are essential parts of effective learning, and competition is often helpful. Read more...
Effective Learning Does Not Emulate the Professional Workplace
The most effective learning techniques require substantial cognitive effort from students and typically do not emulate what experts do in the professional workplace. Direct instruction is necessary to maximize student learning, whereas unguided instruction and group projects are typically very inefficient. Read more...
People Differ in Learning Speed, Not Learning Style
Different people generally have different working memory capacities and learn at different rates, but people do not actually learn better in their preferred “learning style.” Instead, different people need the same form of practice but in different amounts. Read more...
The Story of the Science of Learning
In terms of improving educational outcomes, science is not where the bottleneck is. The bottleneck is in practice. The science of learning has advanced significantly over the past century, yet the practice of education has barely changed. Read more...
Cognitive Science of Learning: How the Brain Works
Cognition involves the flow of information through sensory, working, and long-term memory banks in the brain. Sensory memory temporarily holds raw data, working memory manipulates and organizes information, and long-term memory stores it indefinitely by creating strategic electrical wiring between neurons. Learning amounts to increasing the quantity, depth, retrievability, and generalizability of concepts and skills in a student’s long-term memory. Limited working memory capacity creates a bottleneck in the transfer of information into long-term memory, but cognitive learning strategies can be used to mitigate the effects of this bottleneck. Read more...
Optimized, Individualized Spaced Repetition in Hierarchical Knowledge Structures
Spaced repetition is complicated in hierarchical bodies of knowledge, like mathematics, because repetitions on advanced topics should “trickle down” to update the repetition schedules of simpler topics that are implicitly practiced (while being discounted appropriately since these repetitions are often too early to count for full credit towards the next repetition). However, I developed a model of Fractional Implicit Repetition (FIRe) that not only accounts for implicit “trickle-down” repetitions but also minimizes the number of reviews by choosing reviews whose implicit repetitions “knock out” other due reviews (like dominos), and calibrates the speed of the spaced repetition process to each individual student on each individual topic (student ability and topic difficulty are competing factors). Read more...
The Counterintuitive Nature of Effective Learning Strategies
Effective learning strategies sometimes go against our human instincts about conversation. Read more...
Memory vs Time Graphs
A way to visualize some cognitive learning strategies. Read more...
Algebra
Intuition Behind Polynomial Numerators in Partial Fractions
Each decomposition produces a system of linear equations where the number of unknowns equals the number of equations. Read more...
Educational resources commonly address slant asymptotes. Why not general polynomial asymptotes?
Answer: It’s not very useful (not in practice, not in theory). Read more...
Intuition Behind Completing the Square
Hidden inside of every quadratic, there is a perfect square. Read more...
Graphing Calculator Drawing: Composition Waves and Implicit Trig Patterns
Equations involving compositions of trigonometric functions can create wild patterns in the plane. Read more...
Graphing Calculator Drawing: Lissajous Curves
Lissajous curves use sine functions to create interesting patterns in the plane. Read more...
Graphing Calculator Drawing: Rotation
Absolute value graphs can be rotated to draw stars. Read more...
Graphing Calculator Drawing: Non-Euclidean Ellipses
Non-euclidean ellipses can be used to draw starry-eye sunglasses. Read more...
Graphing Calculator Drawing: Euclidean Ellipses
Euclidean ellipses can be combined with sine wave shading to form three-dimensional shells. Read more...
Graphing Calculator Drawing: Shading with Sine
High-frequency sine waves can be used to draw shaded regions. Read more...
Graphing Calculator Drawing: Roots
Roots can be used to draw deer. Read more...
Graphing Calculator Drawing: Sine Waves
Sine waves can be used to draw scales on a fish. Read more...
Graphing Calculator Drawing: Parabolas
Parabolas can be used to draw a fish. Read more...
Graphing Calculator Drawing: Absolute Value
Absolute value can be used to draw a person. Read more...
Graphing Calculator Drawing: Slanted Lines
Slanted lines can be used to draw a spider web. Read more...
Graphing Calculator Drawing: Horizontal and Vertical Lines
Horizontal and vertical lines can be used to draw a castle. Read more...
Compositions of Functions
Compositions of functions consist of multiple functions linked together, where the output of one function becomes the input of another function. Read more...
Inverse Functions
Inverting a function entails reversing the outputs and inputs of the function. Read more...
Reflections of Functions
When a function is reflected, it flips across one of the axes to become its mirror image. Read more...
Rescalings of Functions
When a function is rescaled, it is stretched or compressed along one of the axes, like a slinky. Read more...
Shifts of Functions
When a function is shifted, all of its points move vertically and/or horizontally by the same amount. Read more...
Piecewise Functions
A piecewise function is pieced together from multiple different functions. Read more...
Trigonometric Functions
Trigonometric functions represent the relationship between sides and angles in right triangles. Read more...
Absolute Value
Absolute value represents the magnitude of a number, i.e. its distance from zero. Read more...
Exponential and Logarithmic Functions
Exponential functions have variables as exponents. Logarithms cancel out exponentiation. Read more...
Radical Functions
Radical functions involve roots: square roots, cube roots, or any kind of fractional exponent in general. Read more...
Graphing Rational Functions with Slant and Polynomial Asymptotes
A slant asymptote is a slanted line that arises from a linear term in the proper form of a rational function. Read more...
Graphing Rational Functions with Horizontal and Vertical Asymptotes
If we choose one input on each side of an asymptote, we can tell which section of the plane the function will occupy. Read more...
Vertical Asymptotes of Rational Functions
Vertical asymptotes are vertical lines that a function approaches but never quite reaches. Read more...
Horizontal Asymptotes of Rational Functions
Rational functions can have a form of end behavior in which they become flat, approaching (but never quite reaching) a horizontal line known as a horizontal asymptote. Read more...
Polynomial Long Division
Polynomial long division works the same way as the long division algorithm that’s familiar from simple arithmetic. Read more...
Sketching Graphs of Polynomials
We can sketch the graph of a polynomial using its end behavior and zeros. Read more...
Rational Roots and Synthetic Division
The rational roots theorem can help us find zeros of polynomials without blindly guessing. Read more...
Zeros of Polynomials
The zeros of a polynomial are the inputs that cause it to evaluate to zero. Read more...
Standard Form and End Behavior of Polynomials
The end behavior of a polynomial refers to the type of output that is produced when we input extremely large positive or negative values. Read more...
Systems of Inequalities
To solve a system of inequalities, we need to solve each individual inequality and find where all their solutions overlap. Read more...
Quadratic Inequalities
Quadratic inequalities are best visualized in the plane. Read more...
Linear Inequalities in the Plane
When a linear equation has two variables, the solution covers a section of the coordinate plane. Read more...
Linear Inequalities in the Number Line
An inequality is similar to an equation, but instead of saying two quantities are equal, it says that one quantity is greater than or less than another. Read more...
Quadratic Systems
Systems of quadratic equations can be solved via substitution. Read more...
Vertex Form
To easily graph a quadratic equation, we can convert it to vertex form. Read more...
Completing the Square
Completing the square helps us gain a better intuition for quadratic equations and understand where the quadratic formula comes from. Read more...
Quadratic Formula
To solve hard-to-factor quadratic equations, it’s easiest to use the quadratic formula. Read more...
Factoring Quadratic Equations
Factoring is a method for solving quadratic equations. Read more...
Standard Form of a Quadratic Equation
Quadratic equations are similar to linear equations, except that they contain squares of a single variable. Read more...
Linear Systems
A linear system consists of multiple linear equations, and the solution of a linear system consists of the pairs that satisfy all of the equations. Read more...
Standard Form of a Line
Standard form makes it easy to see the intercepts of a line. Read more...
Point-Slope Form
An easy way to write the equation of a line if we know the slope and a point on a line. Read more...
Slope-Intercept Form
Introducing linear equations in two variables. Read more...
Solving Linear Equations
Loosely speaking, a linear equation is an equality statement containing only addition, subtraction, multiplication, and division. Read more...
Intuiting Series
A series is the sum of a sequence. Read more...
Intuiting Sequences
A sequence is a list of numbers that has some pattern. Read more...
Intuiting Functions
A function is a scribble that crosses each vertical line only once. Read more...
Blog (Tier 2)
Retrival Practice is F*cking Obvious
In the science of learning, there is absolutely no debate: practice techniques that center around retrieving information directly from one’s brain produce superior learning outcomes compared to techniques that involve re-ingesting information from an external source. Read more...
Learning Higher-Grade Math Ahead of Time is the Greatest Educational/Career Life Hack
Higher-grade math unlocks specialized fields that students normally couldn’t access until much later – and on average, the faster you accelerate your learning, the sooner you get your career started, and the more you accomplish over the course of your career. Read more...
Fortify Your F*cking Fundamentals
Skating around the rink will get you to a decent level of comfort in your basic skating skills, but being able to land jumps and spins will force a whole new level of robustness and fault-tolerance in those underlying skills. The same applies to knowledge in general. Read more...
You Can Effectively Turn Long-Term Memory Into An Extension of Working Memory
The way to do this is to develop automaticity on your lower-level skills. Read more...
Failure Modes in the Talent Development Process
The permastudent, the wannabe, and the dilettante. Read more...
Prereq Yo’ Self Before You Wreck Yo’ Self
If you hammer prerequisite concepts/skills into your long-term memory, get it really solid and easy to retrieve, then you can lessen the load on your working memory, keep it below capacity, avoid getting “broken,” and keep up with the game. Read more...
The Magic You’re Looking For is in the Full-Assed Effort You’re Avoiding
When someone fails to make decent progress towards their learning or fitness goals and cites lack of time as the issue, they’re often wrong. Read more...
How I Would Go About Learning an Arbitrary Subject Where No Full-Fledged Adaptive Learning System is Available
I’m using an LLM to learn biology. My overall conclusion is that IF you could learn successfully, long-term, by self-studying textbooks on your own, and the only thing keeping you from learning a new subject is a slight lack of time, THEN you can probably use LLM prompting to speed up that process a bit, which can help you pull the trigger on learning some stuff you previously didn’t have time for. BUT the vast, vast majority of people are going to need a full-fledged learning system. And even for that miniscule portion of people for whom the “IF” applies… whatever the efficiency gain of LLM prompting over standard textbooks, there’s an even bigger efficiency gain of full-fledged learning system over LLM prompting. Read more...
Competition Math is NOT an All-Encompassing Holy Grail of Math Learning or General Problem Solving
Skill development all comes down to building domain-specific chunks in long-term memory. The way you increase your ability to make mental leaps is not actually by jumping farther, but rather, by building bridges that reduce the distance you need to jump. Read more...
At some point doing the hard thing becomes easier than making the hard thing easier.
And that’s when you have to muster up the willpower to overcome whatever friction is left over. Read more...
How Math Academy Creates its Knowledge Graph
We do it all manually, entirely by hand. Read more...
If You’re Asking Someone to Be Your Mentor then You’re Doing it Wrong
It should look less like them helping you and more like you helping them. Read more...
Math is a Well-Defined Body of Knowledge
At the end of the day, whether or not they know math comes down to whether or not they can apply techniques within that well-defined body of knowledge to solve problems within that well-defined body of knowledge. Read more...
The Necessity of Grinding Through Concrete Examples Before Jumping Up a Level of Abstraction
If you go directly to the most abstract ideas then you’re basically like a kid who reads a book of famous quotes about life and thinks they understand everything about life by way of those quotes. Read more...
How to Cultivate Discipline
Tear down the unproductive habit and build up a counter-habit whose gravity eventually becomes strong enough to completely overtake the original habit. Read more...
Transformation Is Discomforting
What you want is a continual cycle of strain and adaptation. Read more...
Complete Individualization: an Often-Forgotten yet Critical Component of True Deliberate Practice
There are many studies demonstrating a benefit of some component of deliberate practice, but these studies often get mislabeled or misinterpreted as demonstrating the full benefit of true deliberate practice. The field of education is particularly susceptible to this issue because it is impossible for a teacher with a classroom of students to provide a true deliberate practice experience without assistive technology that perfectly emulates the one-on-one pedagogical decisions that an expert tutor would make for each individual student. Read more...
The Importance of Hardcore Skills
Hardcore skill development is necessary to do big things, it’s one of the greatest social mobility hacks, and it gives you the ability/confidence to take risks knowing that you’ll be okay. Read more...
Career Hack: Put Pressure on Your Boss to Come Up with More Work For You
One of the best career hacks – especially for a junior dev – is to knock out your work so quickly and so well that you put pressure on your boss to come up with more work for you. Your boss starts giving you work that they themself need to do soon, which is really the exact kind of work that’s going to move your career forward. Read more...
The Future of Education
To quote a Math Academy student: “The fastest and most rigorous progress will be made by individuals in front of their computers.” Read more...
The Trick to Future-Proof Your Coding Career Against AI
Get yourself into an area that requires deep domain expertise, working on things that haven’t been done or even thoroughly imagined yet. Read more...
Five Steps to Becoming a Fully-Fledged Quantitative Software Engineer
Once you get past steps 1-3, it’s hard to find scaffolding. You can’t just enroll in a course or pick up a textbook. The scaffolding comes from finding a mentor on a mission that you identify with and are well-suited to contribute to. And it can take a lot of searching to find that person and problem area that’s the right fit. Read more...
Why Talent Development is Necessary in Math
When students do the mathematical equivalent of playing kickball during class, and then are expected to do the mathematical equivalent of a backflip at the end of the year, it’s easy to see how struggle and general negative feelings can arise. Read more...
Don’t Undervalue Turning Up the Dial on Your Grind, but Don’t Overvalue the Last Turn
Regret minimization cuts both ways. Read more...
One of the Most Amusing Errors in Teaching
… is asking students to perform activities that leverage a non-existent knowledge base. Read more...
The “Alien-Level Skills” Hack
You get to provide value that nobody else can, and you get recognized for it. Read more...
A White Pill on Cognitive Differences
It’s a hard truth that some people have more advantageous cognitive differences than others – e.g., higher working memory capacity, higher generalization ability, slower forgetting rate. However, there are two sources of hope: 1) automaticity can effectively turn your long-term memory into an extension of your working memory, and 2) many sources of friction in the learning process can be not only remedied but also exploited to increase learning speed beyond the status quo. Read more...
One of the Weirdest, Most Treacherous Math Problems You Will Ever Encounter
A limit problem conjured up from the depths of hell. Read more...
Fast, Correct Answers Do Matter in Mathematics
You gotta develop automaticity on low-level skills in order to free up mental resources for higher-level thinking! Read more...
What’s the Best Way to Teach Math: Explicit Instruction or Less Guided Learning?
Nobody who knows the science of learning is actually debating this. Read more...
When should you do math in your head vs writing it out on paper?
There is an asymmetric tradeoff between 1) blowing your working memory capacity and leaving yourself unable to make progress, versus 2) wasting a couple extra seconds writing down a bit more work than you need to. When in doubt, write it out. Read more...
The Pedagogically Optimal Way to Learn Math
The underlying principle that it all boils down to is deliberate practice. Read more...
Who Needs Worked Examples? You, Eventually.
Math gets hard for different students at different levels. If you don’t have worked examples to help carry you through once math becomes hard for you, then every problem basically blows up into a “research project” for you. Sometimes people advocate for unguided struggle as a way to improve general problem-solving ability, but this idea lacks empirical support. Worked examples won’t prevent you from developing deep understanding (actually, it’s the opposite: worked examples can help you quickly layer on more skills, which forces a structural integrity in the lower levels of your knowledge). Even if you decide against using worked examples for now, continually re-evaluate to make sure you’re getting enough productive training volume. Read more...
How to Crush a Standardized Math Test: SAT/ACT, AP/IB, GRE/GMAT, JEE, etc.
First, you need extensive and solid content knowledge. Then, you need to work through tons of practice exams for the specific exam you’re taking. This might sound simple, but every year, countless people manage to screw it up. Read more...
How Bloom’s Taxonomy Gets Misinterpreted
Many educators think that the makeup of every year in a student’s education should be balanced the same way across Bloom’s taxonomy, whereas Bloom’s 3-stage talent development process suggests that the time allocation should change drastically as a student progresses through their education. Read more...
Higher Math Textbooks and Classes are Typically Not Aligned with the Cognitive Science of Learning
Research indicates the best way to improve your problem-solving ability in any domain is simply by acquiring more foundational skills in that domain. The way you increase your ability to make mental leaps is not actually by jumping farther, but rather, by building bridges that reduce the distance you need to jump. Yet, higher math textbooks & courses seem to focus on trying to train jumping distance instead of bridge-building. Read more...
Why Not Just Learn from a Textbook, MIT OpenCourseWare, Khan Academy, etc.?
I learned from those kinds of resources myself, and while I came a long way, for the amount of effort I put into learning, I could have gone a lot further if my time were used more efficiently. That’s the problem that Math Academy solves. Read more...
The Problem with “Think Really Hard, Struggle for a While, Eventually Solve it or Look Up The Answer” Problems
Challenge problems are not a good use of time until you’ve developed the foundational skills that are necessary to grapple with these problems in a productive and timely fashion. Read more...
What People Think Maximum-Efficiency Learning Should Feel Like, vs What it Actually Feels Like
When you’re developing skills at peak efficiency, you are maximizing the difficulty of your training tasks subject to the constraint that you end up successfully overcoming those difficulties in a timely manner. Read more...
Student Bite Size vs Curriculum Portion Size
Students eat meals of information at similar bite rates when each spoonful fed to them is sized appropriately relative to the size of their mouth. (Note that equal bite rates does not imply equal rates of food volume intake.) Read more...
Review Should Feel Challenging
It’s the act of successfully retrieving fuzzy memory, not clear memory, that extends the memory duration. Read more...
The Vicious Cycle of Forgetting
To transfer information into long-term memory, you need to practice retrieving it without assistance. Read more...
Deliberate Practice: The Most Effective Form of Active Learning
Deliberate practice is the most effective form of active learning. It consists of individualized training activities specially chosen to improve specific aspects of a student’s performance through repetition and successive refinement. It is mindful repetition at the edge of one’s ability, the opposite of mindless repetition within one’s repertoire. The amount of deliberate practice has been shown to be one of the most prominent underlying factors responsible for individual differences in performance across numerous fields, even among highly talented elite performers. Deliberate practice demands effort and intensity, and may be discomforting, but its long-term commitment compounds incremental improvements, leading to expertise. Read more...
Your Mathematical Potential Has a Limit, but it’s Likely Higher Than You Think
Not everybody can learn every level of math, but most people can learn the basics. In practice, however, few people actually reach their full mathematical potential because they get knocked off course early on by factors such as missing foundations, ineffective practice habits, inability or unwillingness to engage in additional practice, or lack of motivation. Read more...
People Differ in Learning Speed, Not Learning Style
Different people generally have different working memory capacities and learn at different rates, but people do not actually learn better in their preferred “learning style.” Instead, different people need the same form of practice but in different amounts. Read more...
Accountability and Incentives are Necessary but Absent in Education
Students and teachers are often not aligned with the goal of maximizing learning, which means that in the absence of accountability and incentives, classrooms are pulled towards a state of mediocrity. Accountability and incentives are typically absent in education, which leads to a “tragedy of the commons” situation where students pass courses (often with high grades) despite severely lacking knowledge of the content. Read more...
Cognitive Science of Learning: How the Brain Works
Cognition involves the flow of information through sensory, working, and long-term memory banks in the brain. Sensory memory temporarily holds raw data, working memory manipulates and organizes information, and long-term memory stores it indefinitely by creating strategic electrical wiring between neurons. Learning amounts to increasing the quantity, depth, retrievability, and generalizability of concepts and skills in a student’s long-term memory. Limited working memory capacity creates a bottleneck in the transfer of information into long-term memory, but cognitive learning strategies can be used to mitigate the effects of this bottleneck. Read more...
Talent Development vs Traditional Schooling
Talent development is not only different from schooling, but in many cases completely orthogonal to schooling. Read more...
Critique of Paper: An astonishing regularity in student learning rate
1) The reported learning rates are actually as quantitatively similar as is suggested by the language used to describe them. 2) The learning rates are measured in a way that rests on a critical assumption that students learn nothing from the initial instruction preceding the practice problems – i.e., you can have one student who learns a lot more from the initial instruction and requires far fewer practice problems, and when you calculate their learning rate, it can come out the same as for a student who learns a lot less from the initial instruction and requires far more practice problems. Read more...
For Most Students, Competition Math is a Waste of Time
If you look at the kinds of math that most quantitative professionals use on a daily basis, competition math tricks don’t show up anywhere. But what does show up everywhere is university-level math subjects. Read more...
The Story of Math Academy’s Eurisko Sequence: the Most Advanced High School Math/CS Sequence in the USA
During its operation from 2020 to 2023, Eurisko was the most advanced high school math/CS sequence in the USA. It culminated in high school students doing masters/PhD-level coursework (reproducing academic research papers in artificial intelligence, building everything from scratch in Python). Read more...
My Experience with Teacher Credentialing and Professional Development
Speaking as someone who had to suffer through a teacher credentialing program… it’s actually an anti-signal when someone references their teaching credential as a qualification to speak about how learning happens. It’s centered around political ideology rather than the science of learning. Read more...
But WHERE do the Taylor Series and Lagrange Error Bound even come from?!
An intuitive derivation. Read more...
Calculus
When Can You Manipulate Differentials Like Fractions?
In general, you can manipulate total derivatives like fractions, but you can’t do the same with partial derivatives. Read more...
But WHERE do the Taylor Series and Lagrange Error Bound even come from?!
An intuitive derivation. Read more...
Trick to Apply the Chain Rule FAST - Peeling the Onion
A simple mnemonic trick for quickly differentiating complicated functions. Read more...
Solving Differential Equations with Taylor Series
Many differential equations don’t have solutions that can be expressed in terms of finite combinations of familiar functions. However, we can often solve for the Taylor series of the solution. Read more...
Manipulating Taylor Series
To find the Taylor series of complicated functions, it’s often easiest to manipulate the Taylor series of simpler functions. Read more...
Taylor Series
Many non-polynomial functions can be represented by infinite polynomials. Read more...
Tests for Convergence
Various tricks for determining whether a series converges or diverges. Read more...
Geometric Series
A geometric series is a sum where each term is some constant times the previous term. Read more...
Variation of Parameters
When we know the solutions of a linear differential equation with constant coefficients and right hand side equal to zero, we can use variation of parameters to find a solution when the right hand side is not equal to zero. Read more...
Integrating Factors
Integrating factors can be used to solve first-order differential equations with non-constant coefficients. Read more...
Undetermined Coefficients
Undetermined coefficients can help us find a solution to a linear differential equation with constant coefficients when the right hand side is not equal to zero. Read more...
Characteristic Polynomial of a Differential Equation
Given a linear differential equation with constant coefficients and a right hand side of zero, the roots of the characteristic polynomial correspond to solutions of the equation. Read more...
Solving Differential Equations by Substitution
Non-separable differential equations can be sometimes converted into separable differential equations by way of substitution. Read more...
Slope Fields and Euler Approximation
When faced with a differential equation that we don’t know how to solve, we can sometimes still approximate the solution. Read more...
Separation of Variables
The simplest differential equations can be solved by separation of variables, in which we move the derivative to one side of the equation and take the antiderivative. Read more...
Improper Integrals
Improper integrals have bounds or function values that extend to positive or negative infinity. Read more...
Integration by Parts
We can apply integration by parts whenever an integral would be made simpler by differentiating some expression within the integral, at the cost of anti-differentiating another expression within the integral. Read more...
Integration by Substitution
Substitution involves condensing an expression of into a single new variable, and then expressing the integral in terms of that new variable. Read more...
Finding Area Using Integrals
To evaluate a definite integral, we find the antiderivative, evaluate it at the indicated bounds, and then take the difference. Read more...
Antiderivatives
The antiderivative of a function is a second function whose derivative is the first function. Read more...
L’Hôpital’s Rule
When a limit takes the indeterminate form of zero divided by zero or infinity divided by infinity, we can differentiate the numerator and denominator separately without changing the actual value of the limit. Read more...
Differentials and Approximation
We can interpret the derivative as an approximation for how a function’s output changes, when the function input is changed by a small amount. Read more...
Finding Extrema
Derivatives can be used to find a function’s local extreme values, its peaks and valleys. Read more...
Derivatives of Non-Polynomial Functions
There are convenient rules the derivatives of exponential, logarithmic, trigonometric, and inverse trigonometric functions. Read more...
Properties of Derivatives
Given a sum, we can differentiate each term individually. But why are we able to do this? Does multiplication work the same way? What about division? Read more...
Chain Rule
When taking derivatives of compositions of functions, we can ignore the inside of a function as long as we multiply by the derivative of the inside afterwards. Read more...
Power Rule for Derivatives
There are some patterns that allow us to compute derivatives without having to compute the limit of the difference quotient. Read more...
Derivatives and the Difference Quotient
The derivative of a function is the function’s slope at a particular point, and can be computed as the limit of the difference quotient. Read more...
Limits by Logarithms, Squeeze Theorem, and Euler’s Constant
Various tricks for evaluating tricky limits. Read more...
Evaluating Limits
The limit of a function, as the input approaches some value, is the output we would expect if we saw only the surrounding portion of the graph. Read more...
Applications of Calculus: Calculating the Horsepower of an Offensive Lineman
It comes out to roughly a fortieth of that of a truck. Read more...
Applications of Calculus: Derivatives in String Art
String art works because the strings are tangent lines to a curve. Read more...
Applications of Calculus: A Failure of Intuition
Calculus can show us how our intuition can fail us, a common theme in philosophy. Read more...
History of Calculus: The Newton-Leibniz Controversy
Nobody came out of the dispute well. Read more...
History of Calculus: The Man who “Broke” Math
When Joseph Fourier first introduced Fourier series, they gave mathematicians nightmares. Read more...
Applications of Calculus: Continuously Compounded Interest
Deriving the “Pert” formula. Read more...
Applications of Calculus: Maximizing Profit
If we know the revenue and costs associated with producing any number of units, then we can use calculus to figure out the number of units to produce for maximum profit. Read more...
Applications of Calculus: Optimization via Gradient Descent
Calculus can be used to find the parameters that minimize a function. Read more...
Applications of Calculus: Physics Engines in Video Games
Physics engines use calculus to periodically updates the locations of objects. Read more...
Applications of Calculus: Rendering 3D Computer Graphics
Introducing Kajiya’s rendering equation. Read more...
Applications of Calculus: Rocket Propulsion
Deriving the ideal rocket equation. Read more...
Applications of Calculus: Modeling Tumor Growth
Deriving the Gompertz function. Read more...
Applications of Calculus: Understanding Plaque Buildup
Understanding why even slight narrowing of arteries can pose such a big problem to blood flow. Read more...
Applications of Calculus: Cardiac Output
Measuring volume of blood the heart pumps out into the aorta per unit time. Read more...
Intuiting Series
A series is the sum of a sequence. Read more...
Intuiting Sequences
A sequence is a list of numbers that has some pattern. Read more...
Intuiting Integrals
Integrals give the area under a portion of a function. Read more...
Intuiting Derivatives
The derivative tells the steepness of a function at a given point, kind of like a carpenter’s level. Read more...
Intuiting Limits
The limit of a function is the height where it looks like the scribble is going to hit a particular vertical line. Read more...
Machine Learning
The Best Neural Nets Textbook That I’ve Seen So Far
“Understanding Deep Learning” by Simon J. D. Prince Read more...
It’s Rare to Find Computation Walkthroughs in ML Learning Resources
Coding tutorials typically just say “import this function then run it,” and the math tutorials typically just say “this is the form of the model, you can fit it using the usual techniques” and leave it to the reader to figure out the rest. Read more...
Hand Computation, Conceptual Debugging, and Coding Projects
The 3 types of problems that I would have students work out back when I was teaching ML. Read more...
ML Courses can Vary Massively in their Coverage
I was coming in with the mindset of “we need to cover the superset of all the content covered in the major textbooks,” which we’re able to do quite well for traditional math. For ML, the rule will have to be amended to “we need to cover the superset of all the content covered in standard university course syllabi.” Read more...
Top-down’s fine for playing around. You’ll run into walls, but don’t give up — go bottom-up to get unstuck.
A little rhyme to understand the big picture of top-down vs bottom-up learning, particularly in the context of machine learning (ML). Read more...
How to get from high school math to cutting-edge ML/AI: a detailed 4-stage roadmap with links to the best learning resources that I’m aware of.
1) Foundational math. 2) Classical machine learning. 3) Deep learning. 4) Cutting-edge machine learning. Read more...
How to Learn Machine Learning: Top Down or Bottom Up?
It can be helpful to take a top-down approach in planning out your overarching learning goals, but the learning itself has to occur bottom-up. Read more...
The Value of Foundational Math Knowledge in Machine Learning
If you start to flail (or, more subtly, doubt yourself and lose interest) after jumping into ML without a baseline level of foundational knowledge, then you need to put your ego aside and re-allocate your time into shoring up your foundations. Read more...
Intuiting Adversarial Examples in Neural Networks via a Simple Computational Experiment
The network becomes book-smart in a particular area but not street-smart in general. The training procedure is like a series of exams on material within a tiny subject area (your data subspace). The network refines its knowledge in the subject area to maximize its performance on those exams, but it doesn’t refine its knowledge outside that subject area. And that leaves it gullible to adversarial examples using inputs outside the subject area. Read more...
Subtle Things to Watch Out For When Demonstrating Lp-Norm Regularization on a High-Degree Polynomial Regression Model
Initial parameter range, data sampling range, severity of regularization. Read more...
How Much Math Do You Need to Know for Machine Learning?
If you know your single-variable calculus, then it’s about 70 hours on Math Academy. Read more...
Reimplementing Blondie24: Convolutional Version
Using convolutional layers to create an even better checkers player. Read more...
Reimplementing Blondie24
Extending Fogel’s tic-tac-toe player to the game of checkers. Read more...
Reimplementing Fogel’s Tic-Tac-Toe Paper
Reimplementing the paper that laid the groundwork for Blondie24. Read more...
Introduction to Blondie24 and Neuroevolution
A method for training neural networks that works even when training feedback is sparse. Read more...
Backpropagation
A convenient technique for computing gradients in neural networks. Read more...
Introduction to Neural Network Regressors
The deeper or more “hierarchical” a computational graph is, the more complex the model that it represents. Read more...
Decision Trees
We can algorithmically build classifiers that use a sequence of nested “if-then” decision rules. Read more...
Naive Bayes
A simple classification algorithm grounded in Bayesian probability. Read more...
K-Nearest Neighbors
One of the simplest classifiers. Read more...
Multiple Regression and Interaction Terms
In many real-life situations, there is more than one input variable that controls the output variable. Read more...
Regression via Gradient Descent
Gradient descent can help us avoid pitfalls that occur when fitting nonlinear models using the pseudoinverse. Read more...
Overfitting, Underfitting, Cross-Validation, and the Bias-Variance Tradeoff
Just because model appears to match closely with points in the data set, does not necessarily mean it is a good model. Read more...
Power, Exponential, and Logistic Regression via Pseudoinverse
Transforming nonlinear functions so that we can fit them using the pseudoinverse. Read more...
Regressing a Linear Combination of Nonlinear Functions via Pseudoinverse
Exploring the most general class of functions that can be fit using the pseudoinverse. Read more...
Linear, Polynomial, and Multiple Linear Regression via Pseudoinverse
Using matrix algebra to fit simple functions to data sets. Read more...
K-Means Clustering
Guess some initial clusters in the data, and then repeatedly update the guesses to make the clusters more cohesive. Read more...
Solving Tower of Hanoi with General Problem Solver
A walkthrough of solving Tower of Hanoi using the approach of one of the earliest AI systems. Read more...
Cutting Through the Hype of AI
Media outlets often make the mistake of anthropomorphizing or attributing human-like characteristics to computer programs. Read more...
The Third Wave of AI: Computation Power and Neural Networks
As computation power increased, neural networks began to take center stage in AI. Read more...
The Second Wave of AI: Expert Systems
Expert systems stored “if-then” rules derived from the knowledge of experts. Read more...
The First Wave of AI: Reasoning as Search
Framing reasoning as searching through a maze of actions for a sequence that achieves the desired end goal. Read more...
What is AI?
Turing test, games, hype, narrow vs general AI. Read more...
Intuiting Ensemble Methods
The type of ensemble model that wins most data science competitions is the stacked model, which consists of an ensemble of entirely different species of models together with some combiner algorithm. Read more...
Intuiting Decision Trees
Decision trees are able to model nonlinear data while remaining interpretable. Read more...
Intuiting Neural Networks
NNs are similar to SVMs in that they project the data to a higher-dimensional space and fit a hyperplane to the data in the projected space. However, whereas SVMs use a predetermined kernel to project the data, NNs automatically construct their own projection. Read more...
Intuiting Support Vector Machines
A Support Vector Machine (SVM) computes the “best” separation between classes as the maximum-margin hyperplane. Read more...
Intuiting Linear Regression
In linear regression, we model the target as a random variable whose expected value depends on a linear combination of the predictors (including a bias term). Read more...
Intuiting Maximum a Posteriori and Maximum Likelihood Estimation
To visualize the relationship between the MAP and MLE estimations, one can imagine starting at the MLE estimation, and then obtaining the MAP estimation by drifting a bit towards higher density in the prior distribution. Read more...
Intuiting Naive Bayes
Naive Bayes classification naively assumes that the presence of a particular feature in a class is unrelated to the presence of any other feature. Read more...
Q&A (Misc)
Q&A: Does Self-Studying Advanced Math Create Bad Habits?
Sure, accelerating via self-study not as optimal as accelerating within teacher-managed courses, but it’s way better than not accelerating at all. Read more...
Q&A
Q&A #3: Sophisticated vs trivial problems, when to learn coding, how I learned SQL
What it means for a problem to be sophisticated, not made trivial by foundational knowledge. When is the best time to learn coding, at an early age or after you have some university-level math under your belt? How I learned to write, organize, and debug big-ass SQL queries. Read more...
Q&A #2: WMC, chunking subskills in LTM, writing down work, using/applying vs deriving/proving
Understanding working memory capacity. Scaffolding new skills by chunking subskills into long-term memory. Why it’s beneficial to write down your work. Why solving problems is necessary. Using/applying mathematical tools vs deriving/proving them. What’s good vs inefficient in the standard math curriculum. Read more...
Recreational Mathematics: Why Focus on Projects Over Puzzles
There’s only so much fun you can have trying to follow another person’s footsteps to arrive at a known solution. There’s only so much confidence you can build from fighting against a problem that someone else has intentionally set up to be well-posed and elegantly solvable if you think about it the right way. Read more...
How I Got Started with Calisthenics
My training has been scattered and fuzzy until recently. Here’s the whole story. Read more...
Recommended Language, Tools, Path, and Curriculum for Teaching Kids to Code
I’d start off with some introductory course that covers the very basics of coding in some language that is used by many professional programmers but where the syntax reads almost like plain English and lower-level details like memory management are abstracted away. Then, I’d jump right into building board games and strategic game-playing agents (so a human can play against the computer), starting with simple games (e.g. tic-tac-toe) and working upwards from there (maybe connect 4 next, then checkers, and so on). Read more...
Tips for Learning Math Effectively
Solving problems, building on top of what you’ve learned, reviewing what you’ve learned, and quality, quantity, and spacing of practice. Read more...
The Easiest Way to Remember Closed vs Open Interval Notation
An oval () fits inside a rectangle [ ] with the same width and height. Read more...
When Can You Manipulate Differentials Like Fractions?
In general, you can manipulate total derivatives like fractions, but you can’t do the same with partial derivatives. Read more...
Teaching
How To Mitigate Nonsense from Lazy/Adversarial Students
Enter grades early on, and (if pre-college) email parents early on. Read more...
Should Students be Asked to Regurgitate Known Proofs?
Imitating without analyzing produces a robot / ape who can’t think critically; analyzing without imitating produces a critic who can’t act on their own advice. Read more...
Subtle Things to Watch Out For When Demonstrating Lp-Norm Regularization on a High-Degree Polynomial Regression Model
Initial parameter range, data sampling range, severity of regularization. Read more...
The Only Way to Teach a More Sophisticated Technique
… is to present a problem where known simpler techniques fail. Read more...
Recommended Language, Tools, Path, and Curriculum for Teaching Kids to Code
I’d start off with some introductory course that covers the very basics of coding in some language that is used by many professional programmers but where the syntax reads almost like plain English and lower-level details like memory management are abstracted away. Then, I’d jump right into building board games and strategic game-playing agents (so a human can play against the computer), starting with simple games (e.g. tic-tac-toe) and working upwards from there (maybe connect 4 next, then checkers, and so on). Read more...
Can You Automate a Math Teacher?
For many (but not all) students, the answer is yes. And for many of those students, automation can unlock life-changing educational outcomes. Read more...
The Abstraction Ceiling: Why it’s Hard to Teach First-Principles Reasoning
As you climb the levels of math, sources of educational friction conspire against you and eventually throw you off the train. And one of the first warning signs is when you stop understanding things at the core, and instead try to memorize special cases cookbook-style. Read more...
The Tragedy of the Commons in Education
Why it’s common for students to pass courses despite severely lacking knowledge of the content. Read more...
For Most Students, Competition Math is a Waste of Time
If you look at the kinds of math that most quantitative professionals use on a daily basis, competition math tricks don’t show up anywhere. But what does show up everywhere is university-level math subjects. Read more...
According to Feynman himself, his classes were a failure for 90% of his students.
While some may view Feynman-style pedagogy as supporting inclusive learning for all students across varying levels of ability, Feynman himself acknowledged that his methods only worked for the top 10% of his students. Read more...
My Experience with Teacher Credentialing and Professional Development
Speaking as someone who had to suffer through a teacher credentialing program… it’s actually an anti-signal when someone references their teaching credential as a qualification to speak about how learning happens. It’s centered around political ideology rather than the science of learning. Read more...
Quants vs Systems Coders
Two subtypes of coders that I watched students grow into. Read more...
Linear Algebra
A Quick Trick for Finding a Matrix Transformation Formula
Perform the desired transformation on identity matrix to get a left-multiplier, and maybe transpose the output. Read more...
Matrix Exponential and Systems of Linear Differential Equations
The matrix exponential can be defined as a power series and used to solve systems of linear differential equations. Read more...
Generalized Eigenvectors and Jordan Form
Jordan form provides a guaranteed backup plan for exponentiating matrices that are non-diagonalizable. Read more...
Recursive Sequence Formulas via Diagonalization
Matrix diagonalization can be applied to construct closed-form expressions for recursive sequences. Read more...
Eigenvalues, Eigenvectors, and Diagonalization
The eigenvectors of a matrix are those vectors that the matrix simply rescales, and the factor by which an eigenvector is rescaled is called its eigenvalue. These concepts can be used to quickly calculate large powers of matrices. Read more...
Inverse Matrices
The inverse of a matrix is a second matrix which undoes the transformation of the first matrix. Read more...
Rescaling, Shearing, and the Determinant
Every square matrix can be decomposed into a product of rescalings and shears. Read more...
Matrix Multiplication
How to multiply a matrix by another matrix. Read more...
Linear Systems as Transformations of Vectors by Matrices
Matrices are vectors whose components are themselves vectors. Read more...
Higher-Order Variation of Parameters
Solving linear systems can sometimes be a necessary component of solving nonlinear systems. Read more...
Shearing, Cramer’s Rule, and Volume by Reduction
Shearing can be used to express the solution of a linear system using ratios of volumes, and also to compute volumes themselves. Read more...
Volume as the Determinant of a Square Linear System
Rich intuition about why the number of solutions to a square linear system is governed by the volume of the parallelepiped formed by the coefficient vectors. Read more...
N-Dimensional Volume Formula
N-dimensional volume generalizes the idea of the space occupied by an object. We can think about N-dimensional volume as being enclosed by N-dimensional vectors. Read more...
Elimination as Vector Reduction
If we interpret linear systems as sets of vectors, then elimination corresponds to vector reduction. Read more...
Span, Subspaces, and Reduction
The span of a set of vectors consists of all vectors that can be made by adding multiples of vectors in the set. We can often reduce a set of vectors to a simpler set with the same span. Read more...
Lines and Planes
A line starts at an initial point and proceeds straight in a constant direction. A plane is a flat sheet that makes a right angle with some particular vector. Read more...
Dot Product and Cross Product
What does it mean to multiply a vector by another vector? Read more...
N-Dimensional Space
N-dimensional space consists of points that have N components. Read more...
Math Academy
How Math Academy Creates its Knowledge Graph
We do it all manually, entirely by hand. Read more...
The Future of Math Facts Practice on Math Academy
And the problem with many existing times tables practice systems. Read more...
ML Courses can Vary Massively in their Coverage
I was coming in with the mindset of “we need to cover the superset of all the content covered in the major textbooks,” which we’re able to do quite well for traditional math. For ML, the rule will have to be amended to “we need to cover the superset of all the content covered in standard university course syllabi.” Read more...
The Future of Education
To quote a Math Academy student: “The fastest and most rigorous progress will be made by individuals in front of their computers.” Read more...
Five Steps to Becoming a Fully-Fledged Quantitative Software Engineer
Once you get past steps 1-3, it’s hard to find scaffolding. You can’t just enroll in a course or pick up a textbook. The scaffolding comes from finding a mentor on a mission that you identify with and are well-suited to contribute to. And it can take a lot of searching to find that person and problem area that’s the right fit. Read more...
The Future of Proof-Based Courses on Math Academy
And why we refer to ourselves as still being “in beta.” Read more...
My Next Big Modeling Project: Behavior Coaching
Even if students are working on exactly the right things, they need to be working exactly the right way to capture the most learning from their time spent working. Read more...
What’s the Highest Sustainable Daily XP on Math Academy?
Around 50-60 XP/day, that is, 50-60 minutes of serious practice per day. Just like the high-end amount of daily exercise you’d expect from people who keep a consistent exercise routine at the gym. Read more...
Record for Most Work Done on Math Academy on a Single Date (as of July 2024)
834 XP = 834 minutes = 14 hours of work in a single day. You’re probably wondering, what kind of person does that much math in a day? Time for a little story. Read more...
If You Want to Learn Math, You Can’t Shy Away from Computation
Learning math with little computation is like learning basketball with little practice on dribbling & ball handling techniques. Read more...
Why Not Just Learn from a Textbook, MIT OpenCourseWare, Khan Academy, etc.?
I learned from those kinds of resources myself, and while I came a long way, for the amount of effort I put into learning, I could have gone a lot further if my time were used more efficiently. That’s the problem that Math Academy solves. Read more...
The Tip of Math Academy’s Technical Iceberg
Our AI system is one of those things that sounds intuitive enough at a high level, but if you start trying to implement it yourself, you quickly run into a mountain of complexity, numerous edge cases, lots of counterintuitive low-level phenomena that take a while to fully wrap your head around. Read more...
The Story of Math Academy’s Eurisko Sequence: the Most Advanced High School Math/CS Sequence in the USA
During its operation from 2020 to 2023, Eurisko was the most advanced high school math/CS sequence in the USA. It culminated in high school students doing masters/PhD-level coursework (reproducing academic research papers in artificial intelligence, building everything from scratch in Python). Read more...
Quants vs Systems Coders
Two subtypes of coders that I watched students grow into. Read more...
The Ultimate High School Computer Science Sequence: 9 Months In
In 9 months, these students went from initially not knowing how to write helper functions to building a machine learning library from scratch. Read more...
Career Advice
Learning Higher-Grade Math Ahead of Time is the Greatest Educational/Career Life Hack
Higher-grade math unlocks specialized fields that students normally couldn’t access until much later – and on average, the faster you accelerate your learning, the sooner you get your career started, and the more you accomplish over the course of your career. Read more...
If You’re Asking Someone to Be Your Mentor then You’re Doing it Wrong
It should look less like them helping you and more like you helping them. Read more...
Some Tips for Junior Devs
1) Learn SQL and how to use a debugger. 2) Never come up emptyhanded, even if you don’t fix the bug. Read more...
Get On the Right Team
You can be the most committed and capable workhorse on the planet, but if you’re on the wrong team, the only thing you’ll change is your team’s allocation of work. Read more...
How to Allocate Your Bandwidth While Searching for Your Mission
One main focus, one semi-focus, and everything else a hobby with whatever time you have left over. Read more...
Failure Modes in People Who Develop Math Skills but Don’t Capitalize On Them via Coding
1) Difficulty grappling with complexity when it grows so big that you can’t fit everything in your head. 2) Lack of understanding or willingness to accept practical constraints of the problem and incorporate them into the solution. 3) Getting distracted by low-ROI features/details. 4) Being unwilling to do “tedious” work. Read more...
What Math To Learn Next After Calculus
Depending on your goals, either A) methods of proof, or B) linear algebra followed by probability & statistics. Read more...
The Importance of Hardcore Skills
Hardcore skill development is necessary to do big things, it’s one of the greatest social mobility hacks, and it gives you the ability/confidence to take risks knowing that you’ll be okay. Read more...
The Trick to Future-Proof Your Coding Career Against AI
Get yourself into an area that requires deep domain expertise, working on things that haven’t been done or even thoroughly imagined yet. Read more...
How do you apply math to CS when so many software engineers say that there is not that much math in coding?
Write code that makes complicated decisions, often involving some kind of inference. Read more...
Motivation
(In Progress) Advice on Upskilling
You’re Not Lazy, You Just Lack a Habit • Don’t have a passion? Go create one. • Make the Habit Easily Repeatable • Don’t Overreact to Bad Days • Aim for Virtuous Cycles • The Importance of Hardcore Skills • Fortify Your F*cking Fundamentals • Why Train? • The Magic You’re Looking For is in the Full-Assed Effort You’re Avoiding • At some point Doing the Hard Thing becomes Easier than Making the Hard Thing Easier • How to Cultivate Discipline • Keep Your Hands On The Boulder Read more...
The Magic You’re Looking For is in the Full-Assed Effort You’re Avoiding
When someone fails to make decent progress towards their learning or fitness goals and cites lack of time as the issue, they’re often wrong. Read more...
At some point doing the hard thing becomes easier than making the hard thing easier.
And that’s when you have to muster up the willpower to overcome whatever friction is left over. Read more...
Make the Habit Easily Repeatable
Start out with a volume of work that’s small enough that you don’t dread doing it again the next day. Read more...
Don’t Undervalue Turning Up the Dial on Your Grind, but Don’t Overvalue the Last Turn
Regret minimization cuts both ways. Read more...
Competition as a Means of Collaboration
The whole idea is that you want the other person to raise the bar on competition and pass you up, so that you’re motivated to come right back and do the same to them. Read more...
Blog (Tier 1)
How To Get a Full Time Software Job During College (5-Step Roadmap)
I worked full time in data science during my last 2 years of undergrad and I’m pretty sure the process to pull this off is reproducible. Read more...
The Pursuit of Real Life Superhero Training
I just want to build a thermodynamic machine that makes people insanely skilled as efficiently as possible. Read more...
Spaced repetition is so similar to weight training that it might as well be called “wait” training.
The fuzzier that memory, the harder it is to lift. The wait creates the weight. Read more...
You Are NOT Lazy, You Just Lack a Habit
The habit is a psychological force field that protects you from all sorts of negative feelings that try to dissuade you from training. Read more...
Why I Recommend Students NOT Take Notes
If you try to keep information close by taking great notes that you can reference all the time… that just PREVENTS you from truly retaining it. Read more...
I’m Writing a Book on the Science of Learning (update: 400-page working draft is freely available)
With the science of learning, it’s less about “keeping up” with what’s happening, and more about “catching up” with what’s already happened. Read more...
The Math Death Spiral: How Knowledge Gaps Lead to Student Failure
Accumulating mathematical knowledge gaps can lead students to reach a tipping point where further learning becomes overwhelming, ultimately causing them to abandon math entirely. Read more...
The Most Superior Form of Training and the Most Hard-Hitting 2 Sentences in All of Talent Development Research
“…[D]eliberate practice requires effort and is not inherently enjoyable. Individuals are motivated to practice because practice improves performance.” Read more...
The Greatest Breakthrough in the Science of Education Over the Last Century
If you understand the interplay between working memory and long-term memory, then then you can actually derive – from first principles – the methods of effective teaching. Read more...
Conversational Dialogue is a Fascinating Distraction for AI in Education
Hard-coding explanations feels tedious, takes a lot of work, and isn’t “sexy” like an AI that generates responses from scratch – but at least it’s not a pipe dream. It’s a practical solution that lets you move on to other components of the AI that are just as important. Read more...
Want to Major in Math at an Elite University? Getting A’s in High School Math is Not Good Enough
If all the knowledge you show up with is high school math and AP Calculus, and you’re not a genius, then you’re going to get your ass handed to you. Read more...
Which Cognitive Psychology Findings are Solid, That Can Be Used to Help Students Learn Better?
There are numerous cognitive learning strategies that 1) can be used to massively improve learning, 2) have been reproduced so many times they might as well be laws of physics, and 3) connect all the way down to the mechanics of what’s going on in the brain. Read more...
If You Want to Learn Algebra, You Need to Have Automaticity on Basic Arithmetic
Solving equations feels smooth when basic arithmetic is automatic – it’s like moving puzzle pieces around, and you just need to identify how they fit together. But without automaticity on basic arithmetic, each puzzle piece is a heavy weight. You struggle to move them at all, much less figure out where they’re supposed to go. Read more...
Lots of People in Education Disagree with the Premise of Maximizing Learning
But in talent development, the optimization problem is clear: an individual’s performance is to be maximized, so the methods used during practice are those that most efficiently convert effort into performance improvements. Read more...
Graphs
Reimplementing Blondie24: Convolutional Version
Using convolutional layers to create an even better checkers player. Read more...
Reimplementing Blondie24
Extending Fogel’s tic-tac-toe player to the game of checkers. Read more...
Reimplementing Fogel’s Tic-Tac-Toe Paper
Reimplementing the paper that laid the groundwork for Blondie24. Read more...
Introduction to Blondie24 and Neuroevolution
A method for training neural networks that works even when training feedback is sparse. Read more...
Reduced Search Depth and Heuristic Evaluation for Connect Four
Combining game-specific human intelligence (heuristics) and generalizable artificial intelligence (minimax on a game tree) Read more...
Minimax Strategy
Repeatedly choosing the action with the best worst-case scenario. Read more...
Canonical and Reduced Game Trees for Tic-Tac-Toe
Building data structures that represent all the possible outcomes of a game. Read more...
Backpropagation
A convenient technique for computing gradients in neural networks. Read more...
Introduction to Neural Network Regressors
The deeper or more “hierarchical” a computational graph is, the more complex the model that it represents. Read more...
Decision Trees
We can algorithmically build classifiers that use a sequence of nested “if-then” decision rules. Read more...
Dijkstra’s Algorithm for Distance and Shortest Paths in Weighted Graphs
Computing spatial relationships between nodes when edges no longer represent unit distances. Read more...
Distance and Shortest Paths in Unweighted Graphs
Using traversals to understand spatial relationships between nodes in graphs. Read more...
Breadth-First and Depth-First Traversals
Graphs show up all the time in computer science, so it’s important to know how to work with them. Read more...
Education
How I Would Go About Learning an Arbitrary Subject Where No Full-Fledged Adaptive Learning System is Available
I’m using an LLM to learn biology. My overall conclusion is that IF you could learn successfully, long-term, by self-studying textbooks on your own, and the only thing keeping you from learning a new subject is a slight lack of time, THEN you can probably use LLM prompting to speed up that process a bit, which can help you pull the trigger on learning some stuff you previously didn’t have time for. BUT the vast, vast majority of people are going to need a full-fledged learning system. And even for that miniscule portion of people for whom the “IF” applies… whatever the efficiency gain of LLM prompting over standard textbooks, there’s an even bigger efficiency gain of full-fledged learning system over LLM prompting. Read more...
The One Skill You Can Acquire By Passively Consuming Information
The ability to say things that sound smart on the surface without actually knowing what you’re talking about. Read more...
One of the Most Amusing Errors in Teaching
… is asking students to perform activities that leverage a non-existent knowledge base. Read more...
Why is there sometimes resistance to automaticity in education?
The need for automaticity on low-level skills is obvious to anyone with experience learning a sport or instrument. So why is there sometimes resistance in education? It makes sense if you think about what people usually find persuasive. Read more...
Student Bite Size vs Curriculum Portion Size
Students eat meals of information at similar bite rates when each spoonful fed to them is sized appropriately relative to the size of their mouth. (Note that equal bite rates does not imply equal rates of food volume intake.) Read more...
A Common Source of Student Mistakes
Many students who pattern-match will tend to prefer solutions requiring fewer and simpler operations, especially if those solutions yield ballpark-reasonable results. Read more...
Critique of Paper: An astonishing regularity in student learning rate
1) The reported learning rates are actually as quantitatively similar as is suggested by the language used to describe them. 2) The learning rates are measured in a way that rests on a critical assumption that students learn nothing from the initial instruction preceding the practice problems – i.e., you can have one student who learns a lot more from the initial instruction and requires far fewer practice problems, and when you calculate their learning rate, it can come out the same as for a student who learns a lot less from the initial instruction and requires far more practice problems. Read more...
Applications
Applications of Calculus: Calculating the Horsepower of an Offensive Lineman
It comes out to roughly a fortieth of that of a truck. Read more...
Applications of Calculus: Derivatives in String Art
String art works because the strings are tangent lines to a curve. Read more...
Applications of Calculus: A Failure of Intuition
Calculus can show us how our intuition can fail us, a common theme in philosophy. Read more...
Applications of Calculus: Continuously Compounded Interest
Deriving the “Pert” formula. Read more...
Applications of Calculus: Maximizing Profit
If we know the revenue and costs associated with producing any number of units, then we can use calculus to figure out the number of units to produce for maximum profit. Read more...
Applications of Calculus: Optimization via Gradient Descent
Calculus can be used to find the parameters that minimize a function. Read more...
Applications of Calculus: Physics Engines in Video Games
Physics engines use calculus to periodically updates the locations of objects. Read more...
Applications of Calculus: Rendering 3D Computer Graphics
Introducing Kajiya’s rendering equation. Read more...
Applications of Calculus: Rocket Propulsion
Deriving the ideal rocket equation. Read more...
Applications of Calculus: Modeling Tumor Growth
Deriving the Gompertz function. Read more...
Applications of Calculus: Understanding Plaque Buildup
Understanding why even slight narrowing of arteries can pose such a big problem to blood flow. Read more...
Applications of Calculus: Cardiac Output
Measuring volume of blood the heart pumps out into the aorta per unit time. Read more...
Graphing Calculator
Graphing Calculator Drawing: Composition Waves and Implicit Trig Patterns
Equations involving compositions of trigonometric functions can create wild patterns in the plane. Read more...
Graphing Calculator Drawing: Lissajous Curves
Lissajous curves use sine functions to create interesting patterns in the plane. Read more...
Graphing Calculator Drawing: Rotation
Absolute value graphs can be rotated to draw stars. Read more...
Graphing Calculator Drawing: Non-Euclidean Ellipses
Non-euclidean ellipses can be used to draw starry-eye sunglasses. Read more...
Graphing Calculator Drawing: Euclidean Ellipses
Euclidean ellipses can be combined with sine wave shading to form three-dimensional shells. Read more...
Graphing Calculator Drawing: Shading with Sine
High-frequency sine waves can be used to draw shaded regions. Read more...
Graphing Calculator Drawing: Roots
Roots can be used to draw deer. Read more...
Graphing Calculator Drawing: Sine Waves
Sine waves can be used to draw scales on a fish. Read more...
Graphing Calculator Drawing: Parabolas
Parabolas can be used to draw a fish. Read more...
Graphing Calculator Drawing: Absolute Value
Absolute value can be used to draw a person. Read more...
Graphing Calculator Drawing: Slanted Lines
Slanted lines can be used to draw a spider web. Read more...
Graphing Calculator Drawing: Horizontal and Vertical Lines
Horizontal and vertical lines can be used to draw a castle. Read more...
Drawing
Graphing Calculator Drawing: Composition Waves and Implicit Trig Patterns
Equations involving compositions of trigonometric functions can create wild patterns in the plane. Read more...
Graphing Calculator Drawing: Lissajous Curves
Lissajous curves use sine functions to create interesting patterns in the plane. Read more...
Graphing Calculator Drawing: Rotation
Absolute value graphs can be rotated to draw stars. Read more...
Graphing Calculator Drawing: Non-Euclidean Ellipses
Non-euclidean ellipses can be used to draw starry-eye sunglasses. Read more...
Graphing Calculator Drawing: Euclidean Ellipses
Euclidean ellipses can be combined with sine wave shading to form three-dimensional shells. Read more...
Graphing Calculator Drawing: Shading with Sine
High-frequency sine waves can be used to draw shaded regions. Read more...
Graphing Calculator Drawing: Roots
Roots can be used to draw deer. Read more...
Graphing Calculator Drawing: Sine Waves
Sine waves can be used to draw scales on a fish. Read more...
Graphing Calculator Drawing: Parabolas
Parabolas can be used to draw a fish. Read more...
Graphing Calculator Drawing: Absolute Value
Absolute value can be used to draw a person. Read more...
Graphing Calculator Drawing: Slanted Lines
Slanted lines can be used to draw a spider web. Read more...
Graphing Calculator Drawing: Horizontal and Vertical Lines
Horizontal and vertical lines can be used to draw a castle. Read more...
Algorithms
Trick to Check Equality of Expression Containing Subscripts Using a Basic LaTeX Expression Evaluator
A silly bug turned genius hack. Read more...
Intuiting Ensemble Methods
The type of ensemble model that wins most data science competitions is the stacked model, which consists of an ensemble of entirely different species of models together with some combiner algorithm. Read more...
Intuiting Decision Trees
Decision trees are able to model nonlinear data while remaining interpretable. Read more...
Intuiting Neural Networks
NNs are similar to SVMs in that they project the data to a higher-dimensional space and fit a hyperplane to the data in the projected space. However, whereas SVMs use a predetermined kernel to project the data, NNs automatically construct their own projection. Read more...
Intuiting Support Vector Machines
A Support Vector Machine (SVM) computes the “best” separation between classes as the maximum-margin hyperplane. Read more...
Intuiting Linear Regression
In linear regression, we model the target as a random variable whose expected value depends on a linear combination of the predictors (including a bias term). Read more...
Intuiting Maximum a Posteriori and Maximum Likelihood Estimation
To visualize the relationship between the MAP and MLE estimations, one can imagine starting at the MLE estimation, and then obtaining the MAP estimation by drifting a bit towards higher density in the prior distribution. Read more...
Intuiting Naive Bayes
Naive Bayes classification naively assumes that the presence of a particular feature in a class is unrelated to the presence of any other feature. Read more...
Research
Paper Idea: A Theory of Optimal Learning Efficiency in Hierarchical Knowledge Structures
An idea for a paper that I don’t currently have the bandwidth to write. Read more...
Student Bite Size vs Curriculum Portion Size
Students eat meals of information at similar bite rates when each spoonful fed to them is sized appropriately relative to the size of their mouth. (Note that equal bite rates does not imply equal rates of food volume intake.) Read more...
Critique of Paper: An astonishing regularity in student learning rate
1) The reported learning rates are actually as quantitatively similar as is suggested by the language used to describe them. 2) The learning rates are measured in a way that rests on a critical assumption that students learn nothing from the initial instruction preceding the practice problems – i.e., you can have one student who learns a lot more from the initial instruction and requires far fewer practice problems, and when you calculate their learning rate, it can come out the same as for a student who learns a lot less from the initial instruction and requires far more practice problems. Read more...
Optimized, Individualized Spaced Repetition in Hierarchical Knowledge Structures
Spaced repetition is complicated in hierarchical bodies of knowledge, like mathematics, because repetitions on advanced topics should “trickle down” to update the repetition schedules of simpler topics that are implicitly practiced (while being discounted appropriately since these repetitions are often too early to count for full credit towards the next repetition). However, I developed a model of Fractional Implicit Repetition (FIRe) that not only accounts for implicit “trickle-down” repetitions but also minimizes the number of reviews by choosing reviews whose implicit repetitions “knock out” other due reviews (like dominos), and calibrates the speed of the spaced repetition process to each individual student on each individual topic (student ability and topic difficulty are competing factors). Read more...
A Game-Theoretic Analysis of Social Distancing During Epidemics
In a simplified problem framing, we investigate the (game-theoretical) usefulness of limiting the number of social connections per person. Read more...
Shaping STDP Neural Networks with Periodic Stimulation: a Theoretical Analysis for the Case of Tree Networks
We solve a special case of how to periodically stimulate a biological neural network to obtain a desired connectivity (in theory). Read more...
A Brief Overview of Spike-Timing Dependent Plasticity (STDP) Learning During Neural Simulation
Implementation notes for STDP learning in a network of Hodgkin-Huxley simulated neurons. Read more...
A Visual, Inductive Proof of Sharkovsky’s Theorem
Many existing proofs are not accessible to young mathematicians or those without experience in the realm of dynamic systems. Read more...
A Formula for the Partial Fractions Decomposition of $x^n/(x-a)^k$
And a proof via double induction. Read more...
Limits and Derivatives
L’Hôpital’s Rule
When a limit takes the indeterminate form of zero divided by zero or infinity divided by infinity, we can differentiate the numerator and denominator separately without changing the actual value of the limit. Read more...
Differentials and Approximation
We can interpret the derivative as an approximation for how a function’s output changes, when the function input is changed by a small amount. Read more...
Finding Extrema
Derivatives can be used to find a function’s local extreme values, its peaks and valleys. Read more...
Derivatives of Non-Polynomial Functions
There are convenient rules the derivatives of exponential, logarithmic, trigonometric, and inverse trigonometric functions. Read more...
Properties of Derivatives
Given a sum, we can differentiate each term individually. But why are we able to do this? Does multiplication work the same way? What about division? Read more...
Chain Rule
When taking derivatives of compositions of functions, we can ignore the inside of a function as long as we multiply by the derivative of the inside afterwards. Read more...
Power Rule for Derivatives
There are some patterns that allow us to compute derivatives without having to compute the limit of the difference quotient. Read more...
Derivatives and the Difference Quotient
The derivative of a function is the function’s slope at a particular point, and can be computed as the limit of the difference quotient. Read more...
Limits by Logarithms, Squeeze Theorem, and Euler’s Constant
Various tricks for evaluating tricky limits. Read more...
Evaluating Limits
The limit of a function, as the input approaches some value, is the output we would expect if we saw only the surrounding portion of the graph. Read more...
Stories
Trick to Check Equality of Expression Containing Subscripts Using a Basic LaTeX Expression Evaluator
A silly bug turned genius hack. Read more...
Record for Most Work Done on Math Academy on a Single Date (as of July 2024)
834 XP = 834 minutes = 14 hours of work in a single day. You’re probably wondering, what kind of person does that much math in a day? Time for a little story. Read more...
How I Won a Heat Capacitor Competition Without a Heat Capacitor
Won first place in a state-level competition by finding and exploiting a loophole in the points scoring logic. Read more...
Business Lessons from Science Fair
The most important things I learned from competing in science fairs had nothing to do with physics or even academics. My main takeaways were actually related to business – in particular, sales and marketing. Read more...
The Story of Math Academy’s Eurisko Sequence: the Most Advanced High School Math/CS Sequence in the USA
During its operation from 2020 to 2023, Eurisko was the most advanced high school math/CS sequence in the USA. It culminated in high school students doing masters/PhD-level coursework (reproducing academic research papers in artificial intelligence, building everything from scratch in Python). Read more...
Minimalist Strength Training, Phase 2: Gaining Mass
Minor changes to increase workout intensity and caloric surplus. Read more...
My Experience with Teacher Credentialing and Professional Development
Speaking as someone who had to suffer through a teacher credentialing program… it’s actually an anti-signal when someone references their teaching credential as a qualification to speak about how learning happens. It’s centered around political ideology rather than the science of learning. Read more...
Minimalist Strength Training, Phase 1: Getting Ripped
Daily 20-30 minute bedroom workout with gymnastic rings hanging from pull-up bar – just as much challenge as weights, but inexpensive and easily portable. Read more...
Quants vs Systems Coders
Two subtypes of coders that I watched students grow into. Read more...
From Procedures to Objects
An aha moment with object-oriented programming. Read more...
Objects
Simplex Method
A technique for maximizing linear expressions subject to linear constraints. Read more...
Hash Tables
Under the hood, dictionaries are hash tables. Read more...
Hodgkin-Huxley Model of Action Potentials in Neurons
Implementing a differential equations model that won the Nobel prize. Read more...
SIR Model For the Spread of Disease
A simple differential equations model that we can plot using multivariable Euler estimation. Read more...
Euler Estimation
Arrays can be used to implement more than just matrices. We can also implement other mathematical procedures like Euler estimation. Read more...
Tic-Tac-Toe and Connect Four
One of the best ways to get practice with object-oriented programming is implementing games. Read more...
K-Means Clustering
Guess some initial clusters in the data, and then repeatedly update the guesses to make the clusters more cohesive. Read more...
Reduced Row Echelon Form and Applications to Matrix Arithmetic
You can use the RREF algorithm to compute determinants much faster than with the recursive cofactor expansion method. Read more...
Basic Matrix Arithmetic
We can use arrays to implement matrices and their associated mathematical operations. Read more...
Regression
Backpropagation
A convenient technique for computing gradients in neural networks. Read more...
Introduction to Neural Network Regressors
The deeper or more “hierarchical” a computational graph is, the more complex the model that it represents. Read more...
Multiple Regression and Interaction Terms
In many real-life situations, there is more than one input variable that controls the output variable. Read more...
Regression via Gradient Descent
Gradient descent can help us avoid pitfalls that occur when fitting nonlinear models using the pseudoinverse. Read more...
Overfitting, Underfitting, Cross-Validation, and the Bias-Variance Tradeoff
Just because model appears to match closely with points in the data set, does not necessarily mean it is a good model. Read more...
Power, Exponential, and Logistic Regression via Pseudoinverse
Transforming nonlinear functions so that we can fit them using the pseudoinverse. Read more...
Regressing a Linear Combination of Nonlinear Functions via Pseudoinverse
Exploring the most general class of functions that can be fit using the pseudoinverse. Read more...
Linear, Polynomial, and Multiple Linear Regression via Pseudoinverse
Using matrix algebra to fit simple functions to data sets. Read more...
Topological Data Analysis
The Data Scientist’s Guide to Topological Data Analysis: Preamble
Bridging the communication gap between academia and industry in the field of TDA. Read more...
Persistent Homology Software: Demonstration of TDA
Demonstrating an open-source implementation of persistent homology techniques in the TDA package for R. Read more...
Intuiting Persistent Homology
Persistent homology provides a way to quantify the topological features that persist over our a data set’s full range of scale. Read more...
Mapper Use-Cases at Aunalytics
At Aunalytics, Mapper outperformed hierarchical clustering in providing granular insights. Read more...
Mapper Use-Cases at Ayasdi
Ayasdi developed commercial Mapper software and sells a subscription service to clients who wish to create topological network visualizations of their data. Read more...
Mapper Software: Demonstration of TDAmapper
Demonstrating an open-source implementation of Mapper in the TDAmapper package for R. Read more...
Intuiting the Mapper Algorithm
Representing a data space’s topology by converting it into a network. Read more...
History
Cutting Through the Hype of AI
Media outlets often make the mistake of anthropomorphizing or attributing human-like characteristics to computer programs. Read more...
The Third Wave of AI: Computation Power and Neural Networks
As computation power increased, neural networks began to take center stage in AI. Read more...
The Second Wave of AI: Expert Systems
Expert systems stored “if-then” rules derived from the knowledge of experts. Read more...
The First Wave of AI: Reasoning as Search
Framing reasoning as searching through a maze of actions for a sequence that achieves the desired end goal. Read more...
What is AI?
Turing test, games, hype, narrow vs general AI. Read more...
History of Calculus: The Newton-Leibniz Controversy
Nobody came out of the dispute well. Read more...
History of Calculus: The Man who “Broke” Math
When Joseph Fourier first introduced Fourier series, they gave mathematicians nightmares. Read more...
Differential Equations
Variation of Parameters
When we know the solutions of a linear differential equation with constant coefficients and right hand side equal to zero, we can use variation of parameters to find a solution when the right hand side is not equal to zero. Read more...
Integrating Factors
Integrating factors can be used to solve first-order differential equations with non-constant coefficients. Read more...
Undetermined Coefficients
Undetermined coefficients can help us find a solution to a linear differential equation with constant coefficients when the right hand side is not equal to zero. Read more...
Characteristic Polynomial of a Differential Equation
Given a linear differential equation with constant coefficients and a right hand side of zero, the roots of the characteristic polynomial correspond to solutions of the equation. Read more...
Solving Differential Equations by Substitution
Non-separable differential equations can be sometimes converted into separable differential equations by way of substitution. Read more...
Slope Fields and Euler Approximation
When faced with a differential equation that we don’t know how to solve, we can sometimes still approximate the solution. Read more...
Separation of Variables
The simplest differential equations can be solved by separation of variables, in which we move the derivative to one side of the equation and take the antiderivative. Read more...
Artificial Intelligence
How to get from high school math to cutting-edge ML/AI: a detailed 4-stage roadmap with links to the best learning resources that I’m aware of.
1) Foundational math. 2) Classical machine learning. 3) Deep learning. 4) Cutting-edge machine learning. Read more...
Solving Tower of Hanoi with General Problem Solver
A walkthrough of solving Tower of Hanoi using the approach of one of the earliest AI systems. Read more...
Cutting Through the Hype of AI
Media outlets often make the mistake of anthropomorphizing or attributing human-like characteristics to computer programs. Read more...
The Third Wave of AI: Computation Power and Neural Networks
As computation power increased, neural networks began to take center stage in AI. Read more...
The Second Wave of AI: Expert Systems
Expert systems stored “if-then” rules derived from the knowledge of experts. Read more...
The First Wave of AI: Reasoning as Search
Framing reasoning as searching through a maze of actions for a sequence that achieves the desired end goal. Read more...
What is AI?
Turing test, games, hype, narrow vs general AI. Read more...
Neural Networks
Intuiting Adversarial Examples in Neural Networks via a Simple Computational Experiment
The network becomes book-smart in a particular area but not street-smart in general. The training procedure is like a series of exams on material within a tiny subject area (your data subspace). The network refines its knowledge in the subject area to maximize its performance on those exams, but it doesn’t refine its knowledge outside that subject area. And that leaves it gullible to adversarial examples using inputs outside the subject area. Read more...
Reimplementing Blondie24: Convolutional Version
Using convolutional layers to create an even better checkers player. Read more...
Reimplementing Blondie24
Extending Fogel’s tic-tac-toe player to the game of checkers. Read more...
Reimplementing Fogel’s Tic-Tac-Toe Paper
Reimplementing the paper that laid the groundwork for Blondie24. Read more...
Introduction to Blondie24 and Neuroevolution
A method for training neural networks that works even when training feedback is sparse. Read more...
Backpropagation
A convenient technique for computing gradients in neural networks. Read more...
Introduction to Neural Network Regressors
The deeper or more “hierarchical” a computational graph is, the more complex the model that it represents. Read more...
Learning
Retrival Practice is F*cking Obvious
In the science of learning, there is absolutely no debate: practice techniques that center around retrieving information directly from one’s brain produce superior learning outcomes compared to techniques that involve re-ingesting information from an external source. Read more...
How I Would Go About Learning an Arbitrary Subject Where No Full-Fledged Adaptive Learning System is Available
I’m using an LLM to learn biology. My overall conclusion is that IF you could learn successfully, long-term, by self-studying textbooks on your own, and the only thing keeping you from learning a new subject is a slight lack of time, THEN you can probably use LLM prompting to speed up that process a bit, which can help you pull the trigger on learning some stuff you previously didn’t have time for. BUT the vast, vast majority of people are going to need a full-fledged learning system. And even for that miniscule portion of people for whom the “IF” applies… whatever the efficiency gain of LLM prompting over standard textbooks, there’s an even bigger efficiency gain of full-fledged learning system over LLM prompting. Read more...
Student Bite Size vs Curriculum Portion Size
Students eat meals of information at similar bite rates when each spoonful fed to them is sized appropriately relative to the size of their mouth. (Note that equal bite rates does not imply equal rates of food volume intake.) Read more...
Tips for Learning Math Effectively
Solving problems, building on top of what you’ve learned, reviewing what you’ve learned, and quality, quantity, and spacing of practice. Read more...
Critique of Paper: An astonishing regularity in student learning rate
1) The reported learning rates are actually as quantitatively similar as is suggested by the language used to describe them. 2) The learning rates are measured in a way that rests on a critical assumption that students learn nothing from the initial instruction preceding the practice problems – i.e., you can have one student who learns a lot more from the initial instruction and requires far fewer practice problems, and when you calculate their learning rate, it can come out the same as for a student who learns a lot less from the initial instruction and requires far more practice problems. Read more...
Study Sessions Should be Short and Frequent as Opposed to Long and Sparse
First, you want to form a habit. Second, you want to operate at peak productivity during your session. Third, you want to minimize the amount you forget between sessions. Read more...
Physics
Shaping STDP Neural Networks with Periodic Stimulation: a Theoretical Analysis for the Case of Tree Networks
We solve a special case of how to periodically stimulate a biological neural network to obtain a desired connectivity (in theory). Read more...
Building an Iron Man Suit: A Physics Workbook
A workbook I created to explain the math and physics behind an Iron Man suit to a student who was interested in the comics / movies. Read more...
The Physics Behind an Egg Drop: A Lively Story
A workbook I created to explain the math and physics behind an egg drop experiment to a student who was interested in Lord of the Rings and Star Wars. Read more...
Sound Waves
A brief overview of sound waves and how they interact with things. Read more...
Detecting Dark Matter
A brief overview of the experimental search for dark matter (XENON, CDMS, PICASSO, COUPP). Read more...
Evidence for the Existence of Dark Matter
Mass discrepancies in galaxies and clusters, cosmic background radiation, the structure of the universe, and big bang nucleosynthesis’s impact on baryon density. Read more...
Integrals
Improper Integrals
Improper integrals have bounds or function values that extend to positive or negative infinity. Read more...
Integration by Parts
We can apply integration by parts whenever an integral would be made simpler by differentiating some expression within the integral, at the cost of anti-differentiating another expression within the integral. Read more...
Integration by Substitution
Substitution involves condensing an expression of into a single new variable, and then expressing the integral in terms of that new variable. Read more...
Finding Area Using Integrals
To evaluate a definite integral, we find the antiderivative, evaluate it at the indicated bounds, and then take the difference. Read more...
Antiderivatives
The antiderivative of a function is a second function whose derivative is the first function. Read more...
Intuiting Integrals
Integrals give the area under a portion of a function. Read more...
Quadratic Equations
Quadratic Systems
Systems of quadratic equations can be solved via substitution. Read more...
Vertex Form
To easily graph a quadratic equation, we can convert it to vertex form. Read more...
Completing the Square
Completing the square helps us gain a better intuition for quadratic equations and understand where the quadratic formula comes from. Read more...
Quadratic Formula
To solve hard-to-factor quadratic equations, it’s easiest to use the quadratic formula. Read more...
Factoring Quadratic Equations
Factoring is a method for solving quadratic equations. Read more...
Standard Form of a Quadratic Equation
Quadratic equations are similar to linear equations, except that they contain squares of a single variable. Read more...
Series
Solving Differential Equations with Taylor Series
Many differential equations don’t have solutions that can be expressed in terms of finite combinations of familiar functions. However, we can often solve for the Taylor series of the solution. Read more...
Manipulating Taylor Series
To find the Taylor series of complicated functions, it’s often easiest to manipulate the Taylor series of simpler functions. Read more...
Taylor Series
Many non-polynomial functions can be represented by infinite polynomials. Read more...
Tests for Convergence
Various tricks for determining whether a series converges or diverges. Read more...
Geometric Series
A geometric series is a sum where each term is some constant times the previous term. Read more...
Games
Reimplementing Blondie24: Convolutional Version
Using convolutional layers to create an even better checkers player. Read more...
Reimplementing Blondie24
Extending Fogel’s tic-tac-toe player to the game of checkers. Read more...
Reimplementing Fogel’s Tic-Tac-Toe Paper
Reimplementing the paper that laid the groundwork for Blondie24. Read more...
Introduction to Blondie24 and Neuroevolution
A method for training neural networks that works even when training feedback is sparse. Read more...
Reduced Search Depth and Heuristic Evaluation for Connect Four
Combining game-specific human intelligence (heuristics) and generalizable artificial intelligence (minimax on a game tree) Read more...
Tic-Tac-Toe and Connect Four
One of the best ways to get practice with object-oriented programming is implementing games. Read more...
Notation
The Easiest Way to Remember Closed vs Open Interval Notation
An oval () fits inside a rectangle [ ] with the same width and height. Read more...
Ambiguous Absolute Value Expressions
Is there a standard “order of operations” for parallel vs nested absolute value expressions, in the absence of clarifying notation? Read more...
How to Look Up the Meaning of an Unknown Math Symbol or Expression
Drawing –> Latex commands –> ChatGPT summary –> Google more info Read more...
Arithmetic
Why 4x8 and 6x8 Are, Perhaps Surprisingly, Some of the Hardest Multiplication Facts for Students to Remember
There’s a cognitive principle behind this: associative interference, the phenomenon that conceptually related pieces of knowledge can interfere with each other’s recall. Read more...
Transcripts
Transcript - Golden Nuggets Podcast #40 (Round 4): How Justin learns, new ML course, the magic of Twitter
Rationale, vision, and progress on Math Academy’s upcoming Machine Learning I course (and after that, Machine Learning II, and possibly a Machine Learning III). Design principles behind good math explanations (it all comes down to concrete numerical examples). Unproductive learning behaviors (and all the different categories: kids vs adults, good-faith vs bad-faith). How to get the most out of your learning tasks. Why I recommend NOT to take notes on Math Academy. What to try first before making a flashcard (which should be a last resort), and how we’re planning to incorporate flashcard-style practice on math facts (not just times tables but also trig identities, derivative rules, etc). Using X/Twitter like a Twitch stream. Read more...
Transcript - Golden Nuggets Podcast #39 (Round 3): MA’s upcoming machine learning course
Rationale, vision, and progress on Math Academy’s upcoming Machine Learning I course (and after that, Machine Learning II, and possibly a Machine Learning III). Design principles behind good math explanations (it all comes down to concrete numerical examples). Unproductive learning behaviors (and all the different categories: kids vs adults, good-faith vs bad-faith). How to get the most out of your learning tasks. Why I recommend NOT to take notes on Math Academy. What to try first before making a flashcard (which should be a last resort), and how we’re planning to incorporate flashcard-style practice on math facts (not just times tables but also trig identities, derivative rules, etc). Using X/Twitter like a Twitch stream. Read more...
Transcript - Golden Nuggets Podcast #37 (Round 2): Balancing learning with creative output
Balancing learning math with doing projects that will get you hired. The role of mentorship. Designing social environments for learning. Why it’s important to let conversations flow out of scope. Misconceptions about “slow and deep” learning. How to create career luck. The sequence of steps that led me to get involved in Math Academy (lots of people ask me about this so here’s the precise timestamp: 1:13:45 - 1:24:45). Strategies to maximize your output. The “magical transition” in the spaced repetition process. Read more...
Transcript - Scraping Bits Podcast #107: Proof Writing, Discovering Math, Expert Systems, Learning Math Like a Language
Why aspiring math majors need to come into university with proof-writing skills. My own journey into learning math. Math as a gigantic tree of knowledge with a trunk that is tall relative to other subjects, but short relative to the length of its branches. The experience of reaching the edge of a subfield (the end of a branch): as the branch gets thinner, the learning resources get sh*tter, and making further progress feels like trudging through tar (so you have to find an area where you just love the tar). How to fall in love with a subject. How to get started with a hard subject that you don’t love: starting with small, easy things and continually compound the volume of work until you’re making serious progress. How to maintain focus and avoid distractions. The characteristics of a math prodigy that I’ve tutored/mentored for 6 years and the extent to which these characteristics can be replicated. How Math Academy’s AI system works at a high level, the story behind how/why we created it, and the stages in its evolution into what it is now. How Math Academy’s AI is different from today’s conventional AI approach: expert systems, not machine learning. How to “train” an expert system by observing and rectifying its shortcomings. How to think about spaced repetition in hierarchical bodies of knowledge where partial repetition credit trickles down through the hierarchy and different topics move through the spaced repetition process at different speeds based on student performance and topic difficulty. Areas for improvement in how Math Academy can help learners get back on the workout wagon after falling off. Why you need to be fully automatic on your times tables, but you don’t need to know how to do three-digit by three-digit multiplication in your head. Analogy between building fluency in math and languages. #1 piece of advice for aspiring math majors. Read more...
Transcript - Golden Nuggets Podcast #35: Optimizing learning efficiency at Math Academy
Why are people quitting their jobs to study math? How to study math like an Olympic athlete. Spaced repetition is like “wait”-lifting. Desirable difficulties. Why achieving automaticity in low-level skills is a necessary for creativity. Why it’s still necessary to learn math in a world with AI. Abstraction ceilings as a result of cognitive differences between individuals and practical constraints in life. How much faster and more efficiently we can learn math (as evidenced by Math Academy’s original school program in Pasadena). Math Academy’s vision and roadmap. Read more...
Transcript - Scraping Bits Podcast #102: Learning Mathematics Like an Athlete
My background. Why learn advanced math early. Thinking mathematically. A “mathematical” / “first principles” approach to getting in shape with minimalist strength training. Benefits of building up knowledge from scratch & how to motivate yourself to do that. Goal-setting & gamification in math & fitness. Maintaining motivation by looking back at long-term progress (what used to be hard is now easy). Traits of successful math learners. How does greatness arise & what are some multipliers on one’s chance of achieving it. How to build habits, solidify them into your identity, and have fun with it. Read more...
Mapper
The Data Scientist’s Guide to Topological Data Analysis: Preamble
Bridging the communication gap between academia and industry in the field of TDA. Read more...
Mapper Use-Cases at Aunalytics
At Aunalytics, Mapper outperformed hierarchical clustering in providing granular insights. Read more...
Mapper Use-Cases at Ayasdi
Ayasdi developed commercial Mapper software and sells a subscription service to clients who wish to create topological network visualizations of their data. Read more...
Mapper Software: Demonstration of TDAmapper
Demonstrating an open-source implementation of Mapper in the TDAmapper package for R. Read more...
Intuiting the Mapper Algorithm
Representing a data space’s topology by converting it into a network. Read more...
Linear Equations and Systems
Linear Systems
A linear system consists of multiple linear equations, and the solution of a linear system consists of the pairs that satisfy all of the equations. Read more...
Standard Form of a Line
Standard form makes it easy to see the intercepts of a line. Read more...
Point-Slope Form
An easy way to write the equation of a line if we know the slope and a point on a line. Read more...
Slope-Intercept Form
Introducing linear equations in two variables. Read more...
Solving Linear Equations
Loosely speaking, a linear equation is an equality statement containing only addition, subtraction, multiplication, and division. Read more...
Rational Functions
Graphing Rational Functions with Slant and Polynomial Asymptotes
A slant asymptote is a slanted line that arises from a linear term in the proper form of a rational function. Read more...
Graphing Rational Functions with Horizontal and Vertical Asymptotes
If we choose one input on each side of an asymptote, we can tell which section of the plane the function will occupy. Read more...
Vertical Asymptotes of Rational Functions
Vertical asymptotes are vertical lines that a function approaches but never quite reaches. Read more...
Horizontal Asymptotes of Rational Functions
Rational functions can have a form of end behavior in which they become flat, approaching (but never quite reaching) a horizontal line known as a horizontal asymptote. Read more...
Polynomial Long Division
Polynomial long division works the same way as the long division algorithm that’s familiar from simple arithmetic. Read more...
Non-Polynomial Functions
Piecewise Functions
A piecewise function is pieced together from multiple different functions. Read more...
Trigonometric Functions
Trigonometric functions represent the relationship between sides and angles in right triangles. Read more...
Absolute Value
Absolute value represents the magnitude of a number, i.e. its distance from zero. Read more...
Exponential and Logarithmic Functions
Exponential functions have variables as exponents. Logarithms cancel out exponentiation. Read more...
Radical Functions
Radical functions involve roots: square roots, cube roots, or any kind of fractional exponent in general. Read more...
Transformations of Functions
Compositions of Functions
Compositions of functions consist of multiple functions linked together, where the output of one function becomes the input of another function. Read more...
Inverse Functions
Inverting a function entails reversing the outputs and inputs of the function. Read more...
Reflections of Functions
When a function is reflected, it flips across one of the axes to become its mirror image. Read more...
Rescalings of Functions
When a function is rescaled, it is stretched or compressed along one of the axes, like a slinky. Read more...
Shifts of Functions
When a function is shifted, all of its points move vertically and/or horizontally by the same amount. Read more...
Vectors
Elimination as Vector Reduction
If we interpret linear systems as sets of vectors, then elimination corresponds to vector reduction. Read more...
Span, Subspaces, and Reduction
The span of a set of vectors consists of all vectors that can be made by adding multiples of vectors in the set. We can often reduce a set of vectors to a simpler set with the same span. Read more...
Lines and Planes
A line starts at an initial point and proceeds straight in a constant direction. A plane is a flat sheet that makes a right angle with some particular vector. Read more...
Dot Product and Cross Product
What does it mean to multiply a vector by another vector? Read more...
N-Dimensional Space
N-dimensional space consists of points that have N components. Read more...
Matrices
Inverse Matrices
The inverse of a matrix is a second matrix which undoes the transformation of the first matrix. Read more...
Rescaling, Shearing, and the Determinant
Every square matrix can be decomposed into a product of rescalings and shears. Read more...
Matrix Multiplication
How to multiply a matrix by another matrix. Read more...
Linear Systems as Transformations of Vectors by Matrices
Matrices are vectors whose components are themselves vectors. Read more...
Simulation
Hodgkin-Huxley Model of Action Potentials in Neurons
Implementing a differential equations model that won the Nobel prize. Read more...
SIR Model For the Spread of Disease
A simple differential equations model that we can plot using multivariable Euler estimation. Read more...
Euler Estimation
Arrays can be used to implement more than just matrices. We can also implement other mathematical procedures like Euler estimation. Read more...
Roulette Wheel Selection
How to sample from a discrete probability distribution. Read more...
Simulating Coin Flips
Estimating probabilities by simulating a large number of random experiments. Read more...
Searching
Multivariable Gradient Descent
Just like single-variable gradient descent, except that we replace the derivative with the gradient vector. Read more...
Single-Variable Gradient Descent
We take an initial guess as to what the minimum is, and then repeatedly use the gradient to nudge that guess further and further “downhill” into an actual minimum. Read more...
Estimating Roots via Bisection Search and Newton-Raphson Method
Bisection search involves repeatedly moving one bound halfway to the other. The Newton-Raphson method involves repeatedly moving our guess to the root of the tangent line. Read more...
Solving Magic Squares via Backtracking
Backtracking can drastically cut down the number of possibilities that must be checked during brute force. Read more...
Brute Force Search with Linear-Encoding Cryptography
Brute force search involves trying every single possibility. Read more...
Active Learning
Deliberate Practice: The Most Effective Form of Active Learning
Deliberate practice is the most effective form of active learning. It consists of individualized training activities specially chosen to improve specific aspects of a student’s performance through repetition and successive refinement. It is mindful repetition at the edge of one’s ability, the opposite of mindless repetition within one’s repertoire. The amount of deliberate practice has been shown to be one of the most prominent underlying factors responsible for individual differences in performance across numerous fields, even among highly talented elite performers. Deliberate practice demands effort and intensity, and may be discomforting, but its long-term commitment compounds incremental improvements, leading to expertise. Read more...
The Neuroscience of Active Learning and Automaticity
Active learning leads to more neural activation than passive learning. Automaticity involves developing strategic neural connections that reduce the amount of effort that the brain has to expend to activate patterns of neurons. Read more...
Active Learning: If You’re Active Half the Time, That’s Still Not Enough
During practice, the elite skaters were over 6 times more active than passive, while non-competitive skaters were nearly as passive as they were active. Read more...
Most Students Don’t Even Pay Attention During Lectures
A startup spent months building a sophisticated lecture tool and raising over half a million dollars in investments – but after observing students in the lecture hall, they completely abandoned the product and called up their investors to return the money. Read more...
What Counts as Active Learning?
True active learning requires every individual student to be actively engaged on every piece of the material to be learned. Read more...
Productivity
The #1 Trick for Super-Productivity
… is interleaving a wide variety of productive work that you enjoy. Read more...
3 Common Areas of Confusion in Talent Development
(especially in math learning) Read more...
The Magic You’re Looking For is in the Full-Assed Effort You’re Avoiding
When someone fails to make decent progress towards their learning or fitness goals and cites lack of time as the issue, they’re often wrong. Read more...
Don’t Undervalue Turning Up the Dial on Your Grind, but Don’t Overvalue the Last Turn
Regret minimization cuts both ways. Read more...
Stream
Q&A #3: Sophisticated vs trivial problems, when to learn coding, how I learned SQL
What it means for a problem to be sophisticated, not made trivial by foundational knowledge. When is the best time to learn coding, at an early age or after you have some university-level math under your belt? How I learned to write, organize, and debug big-ass SQL queries. Read more...
Q&A #2: WMC, chunking subskills in LTM, writing down work, using/applying vs deriving/proving
Understanding working memory capacity. Scaffolding new skills by chunking subskills into long-term memory. Why it’s beneficial to write down your work. Why solving problems is necessary. Using/applying mathematical tools vs deriving/proving them. What’s good vs inefficient in the standard math curriculum. Read more...
The Future of Multistep Tasks on Math Academy
The primary key to motivation, goal-setting, understanding how to apply all the mad skills you’ve learned… it seems like it’s all coming down to multisteps. Read more...
Neuroscience
The Neuroscience of Active Learning and Automaticity
Active learning leads to more neural activation than passive learning. Automaticity involves developing strategic neural connections that reduce the amount of effort that the brain has to expend to activate patterns of neurons. Read more...
Cognitive Science of Learning: How the Brain Works
Cognition involves the flow of information through sensory, working, and long-term memory banks in the brain. Sensory memory temporarily holds raw data, working memory manipulates and organizes information, and long-term memory stores it indefinitely by creating strategic electrical wiring between neurons. Learning amounts to increasing the quantity, depth, retrievability, and generalizability of concepts and skills in a student’s long-term memory. Limited working memory capacity creates a bottleneck in the transfer of information into long-term memory, but cognitive learning strategies can be used to mitigate the effects of this bottleneck. Read more...
The Brain in One Sentence
The brain is a neuronal network integrating specialized subsystems that use local competition and thresholding to sparsify input, spike-timing dependent plasticity to learn inference, and layering to implement hierarchical predictive learning. Read more...
Shaping STDP Neural Networks with Periodic Stimulation: a Theoretical Analysis for the Case of Tree Networks
We solve a special case of how to periodically stimulate a biological neural network to obtain a desired connectivity (in theory). Read more...
Limits
Intuiting Limits
The limit of a function is the height where it looks like the scribble is going to hit a particular vertical line. Read more...
Inequalities
Systems of Inequalities
To solve a system of inequalities, we need to solve each individual inequality and find where all their solutions overlap. Read more...
Quadratic Inequalities
Quadratic inequalities are best visualized in the plane. Read more...
Linear Inequalities in the Plane
When a linear equation has two variables, the solution covers a section of the coordinate plane. Read more...
Linear Inequalities in the Number Line
An inequality is similar to an equation, but instead of saying two quantities are equal, it says that one quantity is greater than or less than another. Read more...
Polynomials
Sketching Graphs of Polynomials
We can sketch the graph of a polynomial using its end behavior and zeros. Read more...
Rational Roots and Synthetic Division
The rational roots theorem can help us find zeros of polynomials without blindly guessing. Read more...
Zeros of Polynomials
The zeros of a polynomial are the inputs that cause it to evaluate to zero. Read more...
Standard Form and End Behavior of Polynomials
The end behavior of a polynomial refers to the type of output that is produced when we input extremely large positive or negative values. Read more...
Python
Introductory Python: Functions
Rather than duplicating such code each time we want to use it, it is more efficient to store the code in a function. Read more...
Introductory Python: If, While, and For
We often wish to tell the computer instructions involving the words “if,” “while,” and “for.” Read more...
Introductory Python: Lists, Dictionaries, and Arrays
We can store many related pieces of data within a single variable called a data structure. Read more...
Introductory Python: Strings, Ints, Floats, and Booleans
We can store and manipulate data in the form of variables. Read more...
Volume
Higher-Order Variation of Parameters
Solving linear systems can sometimes be a necessary component of solving nonlinear systems. Read more...
Shearing, Cramer’s Rule, and Volume by Reduction
Shearing can be used to express the solution of a linear system using ratios of volumes, and also to compute volumes themselves. Read more...
Volume as the Determinant of a Square Linear System
Rich intuition about why the number of solutions to a square linear system is governed by the volume of the parallelepiped formed by the coefficient vectors. Read more...
N-Dimensional Volume Formula
N-dimensional volume generalizes the idea of the space occupied by an object. We can think about N-dimensional volume as being enclosed by N-dimensional vectors. Read more...
Eigenspace
Matrix Exponential and Systems of Linear Differential Equations
The matrix exponential can be defined as a power series and used to solve systems of linear differential equations. Read more...
Generalized Eigenvectors and Jordan Form
Jordan form provides a guaranteed backup plan for exponentiating matrices that are non-diagonalizable. Read more...
Recursive Sequence Formulas via Diagonalization
Matrix diagonalization can be applied to construct closed-form expressions for recursive sequences. Read more...
Eigenvalues, Eigenvectors, and Diagonalization
The eigenvectors of a matrix are those vectors that the matrix simply rescales, and the factor by which an eigenvector is rescaled is called its eigenvalue. These concepts can be used to quickly calculate large powers of matrices. Read more...
Hello World
Cartesian Product
Implementing the Cartesian product provides good practice working with arrays. Read more...
Recursive Sequences
Sequences where each term is a function of the previous terms. Read more...
Converting Between Binary, Decimal, and Hexadecimal
There are other number systems that use more or fewer than ten characters. Read more...
Some Short Introductory Coding Exercises
It’s assumed that you’ve had some basic exposure to programming. Read more...
Computer Science
The Story of Math Academy’s Eurisko Sequence: the Most Advanced High School Math/CS Sequence in the USA
During its operation from 2020 to 2023, Eurisko was the most advanced high school math/CS sequence in the USA. It culminated in high school students doing masters/PhD-level coursework (reproducing academic research papers in artificial intelligence, building everything from scratch in Python). Read more...
Quants vs Systems Coders
Two subtypes of coders that I watched students grow into. Read more...
From Procedures to Objects
An aha moment with object-oriented programming. Read more...
The Ultimate High School Computer Science Sequence: 9 Months In
In 9 months, these students went from initially not knowing how to write helper functions to building a machine learning library from scratch. Read more...
Neuroevolution
Reimplementing Blondie24: Convolutional Version
Using convolutional layers to create an even better checkers player. Read more...
Reimplementing Blondie24
Extending Fogel’s tic-tac-toe player to the game of checkers. Read more...
Reimplementing Fogel’s Tic-Tac-Toe Paper
Reimplementing the paper that laid the groundwork for Blondie24. Read more...
Introduction to Blondie24 and Neuroevolution
A method for training neural networks that works even when training feedback is sparse. Read more...
Blondie24
Reimplementing Blondie24: Convolutional Version
Using convolutional layers to create an even better checkers player. Read more...
Reimplementing Blondie24
Extending Fogel’s tic-tac-toe player to the game of checkers. Read more...
Reimplementing Fogel’s Tic-Tac-Toe Paper
Reimplementing the paper that laid the groundwork for Blondie24. Read more...
Introduction to Blondie24 and Neuroevolution
A method for training neural networks that works even when training feedback is sparse. Read more...
Quant
Why I Don’t Worship at the Altar of Neural Nets
In order to justify using a more complex model, the increase in performance has to be worth the cost of integrating and maintaining the complexity. Read more...
Quants vs Systems Coders
Two subtypes of coders that I watched students grow into. Read more...
Tips for Developing Valuable Models
Stuff you don’t find in math textbooks. Read more...
The 5 Breeds of Quants
… are summarized in the following table. Read more...
Tips
Go Through the Question Bank Breadth-First, not Depth-First
An easy trick to improve your retention while working through a bank of review or challenge problems like LeetCode, HackerRank, etc. Read more...
Recreational Mathematics: Why Focus on Projects Over Puzzles
There’s only so much fun you can have trying to follow another person’s footsteps to arrive at a known solution. There’s only so much confidence you can build from fighting against a problem that someone else has intentionally set up to be well-posed and elegantly solvable if you think about it the right way. Read more...
Selecting a Good Problem to Work On
Good problem = intersection between your own interests/talents, the realm of what’s feasible, and the desires of the external world. Read more...
Tips for Developing Valuable Models
Stuff you don’t find in math textbooks. Read more...
Strength Training
Minimalist Strength Training, Phase 2: Gaining Mass
Minor changes to increase workout intensity and caloric surplus. Read more...
Minimalist Strength Training, Phase 1: Getting Ripped
Daily 20-30 minute bedroom workout with gymnastic rings hanging from pull-up bar – just as much challenge as weights, but inexpensive and easily portable. Read more...
Blog (Pinned)
How to get from high school math to cutting-edge ML/AI: a detailed 4-stage roadmap with links to the best learning resources that I’m aware of.
1) Foundational math. 2) Classical machine learning. 3) Deep learning. 4) Cutting-edge machine learning. Read more...
Why is the EdTech Industry So Damn Soft?
The hard truth is that if you want to build a serious educational product, you can’t be afraid to charge money for it. You can’t back yourself into a corner where you depend on a massive userbase. Why? Because most people are not serious about learning, and if you depend on a massive base of unserious learners, then you have to employ ineffective learning strategies that do not repel unserious students. Which makes your product suck. Read more...
The Greatest Educational Life Hack: Learning Math Ahead of Time
Learning math early guards you against numerous academic risks and opens all kinds of doors to career opportunities. Read more...
Optimized, Individualized Spaced Repetition in Hierarchical Knowledge Structures
Spaced repetition is complicated in hierarchical bodies of knowledge, like mathematics, because repetitions on advanced topics should “trickle down” to update the repetition schedules of simpler topics that are implicitly practiced (while being discounted appropriately since these repetitions are often too early to count for full credit towards the next repetition). However, I developed a model of Fractional Implicit Repetition (FIRe) that not only accounts for implicit “trickle-down” repetitions but also minimizes the number of reviews by choosing reviews whose implicit repetitions “knock out” other due reviews (like dominos), and calibrates the speed of the spaced repetition process to each individual student on each individual topic (student ability and topic difficulty are competing factors). Read more...
Proofs
Persistent Homology
The Data Scientist’s Guide to Topological Data Analysis: Preamble
Bridging the communication gap between academia and industry in the field of TDA. Read more...
Persistent Homology Software: Demonstration of TDA
Demonstrating an open-source implementation of persistent homology techniques in the TDA package for R. Read more...
Intuiting Persistent Homology
Persistent homology provides a way to quantify the topological features that persist over our a data set’s full range of scale. Read more...
Videos
But WHERE do the Taylor Series and Lagrange Error Bound even come from?!
An intuitive derivation. Read more...
Trick to Apply the Chain Rule FAST - Peeling the Onion
A simple mnemonic trick for quickly differentiating complicated functions. Read more...
Intuition Behind Completing the Square
Hidden inside of every quadratic, there is a perfect square. Read more...
Geometry
Thales’ Theorem
Every inscribed triangle whose hypotenuse is a diameter is a right triangle. Read more...
Multivariable Calculus
One of the Weirdest, Most Treacherous Math Problems You Will Ever Encounter
A limit problem conjured up from the depths of hell. Read more...
How to Remember Type I, II, and III Regions in Multivariable Calculus
Type I pairs with the variable that runs vertically in the usual representation of the coordinate system. The remaining types are paired with the rest of the variables in ascending order. Read more...
Path Dependency in Multivariable Limits
The behavior of a multivariable function can be highly specific to the path taken. Read more...
Eurisko
The Story of Math Academy’s Eurisko Sequence: the Most Advanced High School Math/CS Sequence in the USA
During its operation from 2020 to 2023, Eurisko was the most advanced high school math/CS sequence in the USA. It culminated in high school students doing masters/PhD-level coursework (reproducing academic research papers in artificial intelligence, building everything from scratch in Python). Read more...
Quants vs Systems Coders
Two subtypes of coders that I watched students grow into. Read more...
The Ultimate High School Computer Science Sequence: 9 Months In
In 9 months, these students went from initially not knowing how to write helper functions to building a machine learning library from scratch. Read more...
Classification
Decision Trees
We can algorithmically build classifiers that use a sequence of nested “if-then” decision rules. Read more...
Naive Bayes
A simple classification algorithm grounded in Bayesian probability. Read more...
K-Nearest Neighbors
One of the simplest classifiers. Read more...
Calisthenics
How I Got Started with Calisthenics
My training has been scattered and fuzzy until recently. Here’s the whole story. Read more...
Student Errors
Expository
A Brief Overview of Spike-Timing Dependent Plasticity (STDP) Learning During Neural Simulation
Implementation notes for STDP learning in a network of Hodgkin-Huxley simulated neurons. Read more...
A Visual, Inductive Proof of Sharkovsky’s Theorem
Many existing proofs are not accessible to young mathematicians or those without experience in the realm of dynamic systems. Read more...
Category Theory
Making Indirect Interactions Explicit in Networks
Category theory provides a language for explicitly describing indirect relationships in graphs. Read more...
Book Summary: Memory Evolutive Systems
Framing complex systems in the language of category theory. Read more...
Functions
Intuiting Functions
A function is a scribble that crosses each vertical line only once. Read more...
Sequences
Intuiting Series
A series is the sum of a sequence. Read more...
Intuiting Sequences
A sequence is a list of numbers that has some pattern. Read more...
Sorting
Merge Sort and Quicksort
Merge sort and quicksort are generally faster than selection, bubble, and insertion sort. And unlike counting sort, they are not susceptible to blowup in the amount of memory required. Read more...
Selection, Bubble, Insertion, and Counting Sort
Some of the simplest methods for sorting items in arrays. Read more...
Game Trees
Minimax Strategy
Repeatedly choosing the action with the best worst-case scenario. Read more...
Canonical and Reduced Game Trees for Tic-Tac-Toe
Building data structures that represent all the possible outcomes of a game. Read more...
Gymnastic Rings
Minimalist Strength Training, Phase 2: Gaining Mass
Minor changes to increase workout intensity and caloric surplus. Read more...
Minimalist Strength Training, Phase 1: Getting Ripped
Daily 20-30 minute bedroom workout with gymnastic rings hanging from pull-up bar – just as much challenge as weights, but inexpensive and easily portable. Read more...
Gifted Students
Educational Acceleration
Science Fair
How I Won a Heat Capacitor Competition Without a Heat Capacitor
Won first place in a state-level competition by finding and exploiting a loophole in the points scoring logic. Read more...
Business Lessons from Science Fair
The most important things I learned from competing in science fairs had nothing to do with physics or even academics. My main takeaways were actually related to business – in particular, sales and marketing. Read more...
Grading
Back to Top ↑Intelligence
The Abstraction Ceiling: Why it’s Hard to Teach First-Principles Reasoning
As you climb the levels of math, sources of educational friction conspire against you and eventually throw you off the train. And one of the first warning signs is when you stop understanding things at the core, and instead try to memorize special cases cookbook-style. Read more...
Absolute Value
Ambiguous Absolute Value Expressions
Is there a standard “order of operations” for parallel vs nested absolute value expressions, in the absence of clarifying notation? Read more...
AI
Conversational Dialogue is a Fascinating Distraction for AI in Education
Hard-coding explanations feels tedious, takes a lot of work, and isn’t “sexy” like an AI that generates responses from scratch – but at least it’s not a pipe dream. It’s a practical solution that lets you move on to other components of the AI that are just as important. Read more...
Can You Automate a Math Teacher?
For many (but not all) students, the answer is yes. And for many of those students, automation can unlock life-changing educational outcomes. Read more...
Logic
Career
Career Hack: Put Pressure on Your Boss to Come Up with More Work For You
One of the best career hacks – especially for a junior dev – is to knock out your work so quickly and so well that you put pressure on your boss to come up with more work for you. Your boss starts giving you work that they themself need to do soon, which is really the exact kind of work that’s going to move your career forward. Read more...
Technical Diary
Intuiting Adversarial Examples in Neural Networks via a Simple Computational Experiment
The network becomes book-smart in a particular area but not street-smart in general. The training procedure is like a series of exams on material within a tiny subject area (your data subspace). The network refines its knowledge in the subject area to maximize its performance on those exams, but it doesn’t refine its knowledge outside that subject area. And that leaves it gullible to adversarial examples using inputs outside the subject area. Read more...
Subtle Things to Watch Out For When Demonstrating Lp-Norm Regularization on a High-Degree Polynomial Regression Model
Initial parameter range, data sampling range, severity of regularization. Read more...
Test Prep
How to Maximize Performance on a Standardized Math Test
If any student, anywhere, is looking for advice on how to prepare for a standardized math test, then this is everything I’d tell them. Read more...
How to Crush a Standardized Math Test: SAT/ACT, AP/IB, GRE/GMAT, JEE, etc.
First, you need extensive and solid content knowledge. Then, you need to work through tons of practice exams for the specific exam you’re taking. This might sound simple, but every year, countless people manage to screw it up. Read more...
Advice
(In Progress) Advice on Upskilling
You’re Not Lazy, You Just Lack a Habit • Don’t have a passion? Go create one. • Make the Habit Easily Repeatable • Don’t Overreact to Bad Days • Aim for Virtuous Cycles • The Importance of Hardcore Skills • Fortify Your F*cking Fundamentals • Why Train? • The Magic You’re Looking For is in the Full-Assed Effort You’re Avoiding • At some point Doing the Hard Thing becomes Easier than Making the Hard Thing Easier • How to Cultivate Discipline • Keep Your Hands On The Boulder Read more...
Humanities
On the Contrasting Educations and Outcomes of Ben Franklin and Montaigne
Montaigne’s education, strictly dictated by his parents and university studies, resulted in an isolative work with scholarly impact but limited public reach. Conversely, Benjamin Franklin’s goal-oriented self-teaching led to influential creations and roles benefiting his community and nation. Read more...
Computers
Introduction to Computers
The main ideas behind computers can be understood by anyone. Read more...
Book Summaries
Book Summary: Memory Evolutive Systems
Framing complex systems in the language of category theory. Read more...
Game Theory
A Game-Theoretic Analysis of Social Distancing During Epidemics
In a simplified problem framing, we investigate the (game-theoretical) usefulness of limiting the number of social connections per person. Read more...
Homology
Intuiting Persistent Homology
Persistent homology provides a way to quantify the topological features that persist over our a data set’s full range of scale. Read more...
Derivatives
Intuiting Derivatives
The derivative tells the steepness of a function at a given point, kind of like a carpenter’s level. Read more...
LaTeX
Tips for LaTeX Math Formatting
How to avoid some of the most common pitfalls leading to ugly LaTeX. Read more...
Linear Programming
Simplex Method
A technique for maximizing linear expressions subject to linear constraints. Read more...
Archetypes
The 5 Breeds of Quants
… are summarized in the following table. Read more...
Tensors
Back to Top ↑Personal Website
Back to Top ↑College Applications
Back to Top ↑Syllabus
Back to Top ↑Differentials
When Can You Manipulate Differentials Like Fractions?
In general, you can manipulate total derivatives like fractions, but you can’t do the same with partial derivatives. Read more...
Terminology
Back to Top ↑Education Policy
Back to Top ↑Math Wars
Back to Top ↑Learning Strategies
Back to Top ↑Riddles
My Go-To Math Riddle: How Many Squares are in a 10 x 10 Grid?
Q: Draw a 10 x 10 square grid. How many squares are there in total? Not just 1 x 1 squares, but also 2 x 2 squares, 3 x 3 squares, and so on. A: The total number of square shapes is the total sum of square numbers 1 + 4 + 9 + 16 + … + 100. Read more...
Probability
Back to Top ↑Competition Math
Back to Top ↑Moore Method
Back to Top ↑Project-Based Learning
Back to Top ↑Datasets
Back to Top ↑Automaticity
The Neuroscience of Active Learning and Automaticity
Active learning leads to more neural activation than passive learning. Automaticity involves developing strategic neural connections that reduce the amount of effort that the brain has to expend to activate patterns of neurons. Read more...
Deliberate Practice
Deliberate Practice: The Most Effective Form of Active Learning
Deliberate practice is the most effective form of active learning. It consists of individualized training activities specially chosen to improve specific aspects of a student’s performance through repetition and successive refinement. It is mindful repetition at the edge of one’s ability, the opposite of mindless repetition within one’s repertoire. The amount of deliberate practice has been shown to be one of the most prominent underlying factors responsible for individual differences in performance across numerous fields, even among highly talented elite performers. Deliberate practice demands effort and intensity, and may be discomforting, but its long-term commitment compounds incremental improvements, leading to expertise. Read more...
Mastery Learning
A Brief History of Mastery Learning
Mastery learning is a strategy in which students demonstrate proficiency on prerequisites before advancing. While even loose approximations of mastery learning have been shown to produce massive gains in student learning, mastery learning faces limited adoption due to clashing with traditional teaching methods and placing increased demands on educators. True mastery learning at a fully granular level requires fully individualized instruction and is only attainable through one-on-one tutoring. Read more...
Bayesian Statistics
Estimating a Visitation Interval: an Exercise in Bivariate Bayesian Statistics
Loosely inspired by the German tank problem: several witnesses reported seeing a UFO during the given time intervals, and you want to quantify your certainty regarding when the UFO arrived and when it left. Read more...
Math Competitions
Self-Study
Q&A: Does Self-Studying Advanced Math Create Bad Habits?
Sure, accelerating via self-study not as optimal as accelerating within teacher-managed courses, but it’s way better than not accelerating at all. Read more...
Learning Efficiency
What People Think Maximum-Efficiency Learning Should Feel Like, vs What it Actually Feels Like
When you’re developing skills at peak efficiency, you are maximizing the difficulty of your training tasks subject to the constraint that you end up successfully overcoming those difficulties in a timely manner. Read more...
Working Memory
Individual Variation in Working Memory Capacity (WMC): a First Step Down the Research Rabbit Hole
There are many, many studies that measure variation in WMC vs variation in other metrics. Read more...
Book Reviews
Book Review: Developing Talent in Young People by Benjamin Bloom
Bloom studied the training backgrounds of 120 world-class talented individuals across 6 talent domains: piano, sculpting, swimming, tennis, math, & neurology, and what he discovered was that talent development occurs through a similar general process, no matter what talent domain. In other words, there is a “formula” for developing talent – though executing it is a lot harder than simply understanding it. Read more...
Startups
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Back to Top ↑Edtech
The Image I Want to Put in People’s Minds When They Think About Edtech
People acquiring impressive skills so quickly that it’s mind-bending. Read more...