Coding & Math Fundamentals: The Free Curriculum
AI tools amplify what you understand — they don’t replace it. A student who knows why the code works directs AI tools ten times better than one who doesn’t. This is our verified list of the best genuinely-free places to build those foundations, in both tracks: math (the logic under everything) and coding/CS. We checked every link and — more importantly — every “free” claim, because this space is full of freemium traps dressed up as free resources. The biggest one we rejected is at the bottom.
Math
Khan Academy — Math
The complete K-through-college math ladder — arithmetic to AP Calculus and Statistics — with videos, mastery-based practice, and instant feedback. The single best structured spine for filling gaps or getting ahead.
What’s free: Everything, always — nonprofit, no freemium tier exists.
Ages 11–19, all levels Math
Art of Problem Solving (AoPS)
The home of competition math (AMC, MATHCOUNTS, olympiad culture) — where mathematically ambitious teens go beyond school math.
What’s free: Alcumus (adaptive problem trainer), instructional videos, forums, and practice contests are free. The famous online classes and textbooks cost money.
Ages 12–18, strong/motivated students Math
3Blue1Brown
Grant Sanderson's animated visual math — Essence of Calculus, Essence of Linear Algebra, and the neural-network series that bridges straight into how AI actually works. Builds intuition no textbook matches.
What’s free: All lessons and videos (Patreon is early-access only, not a paywall).
Ages 14–19 (younger for the curious) Both
Project Euler
Nearly 1,000 problems that require both mathematical thinking and code to solve — the canonical bridge between the two tracks.
What’s free: Completely free, no paid anything.
Ages 14–19, with some programming Both
Desmos
The browser graphing calculator that's become the classroom and standardized-test standard — instant, beautiful, zero-install.
What’s free: All calculators free (paid products target schools, not students).
Ages 11–19, all levels Math
GeoGebra
Free graphing, geometry, 3D, and scientific tools plus thousands of interactive community applets — stronger than Desmos for geometry constructions and 3D.
What’s free: All tools free.
Ages 11–19, all levels Math
Paul's Online Math Notes
A Lamar University professor's famously clear notes for algebra through Calc III and differential equations, with worked practice problems and downloadable cheat sheets.
What’s free: Everything, including all the PDFs.
Ages 15–19 — ideal for AP and early college Math
BetterExplained
"Aha-first" essays on e, π, logarithms, calculus, and trig — the fix for "I can compute it but I don't get it."
What’s free: All articles and the online calculus course (optional ebook is paid).
Ages 13–19 Math
Note: An evergreen reference library, not an active blog — treat it as a place to look things up, not a course to follow.
Coding & computer science
Khan Academy — Intro to Computer Science: Python
The new Python-first intro course with an in-browser editor that even works on tablets. The gentlest serious on-ramp on this list.
What’s free: 100% free (skip their older legacy JavaScript courses — this is the one to start with).
Ages 11–15, absolute beginners Coding
Harvard CS50x
Harvard's legendary intro to computer science — computational thinking, C, Python, SQL, web. The gold-standard first serious CS course.
What’s free: All material and problem sets, plus a free CS50 certificate for completing the work (only the edX verified certificate costs money).
Ages 15–19, beginner-friendly but rigorous Coding
Automate the Boring Stuff with Python
Al Sweigart's practical Python book — spreadsheets, files, web scraping, automation. Teens see code doing genuinely useful things fast.
What’s free: The entire current (3rd) edition free online under Creative Commons.
Ages 13–19 Coding
Eloquent JavaScript
The standard free JavaScript book (4th edition), with in-browser sandboxes and exercises — more intellectually serious than typical web tutorials.
What’s free: Full book online plus free PDF/EPUB downloads; only the paperback is paid.
Ages 14–19, beginners with patience Coding
freeCodeCamp
Project-based certifications in web development, JavaScript, Python, and data science — roughly 300 hours each, earned by building real projects in the browser.
What’s free: "Every aspect… 100% free. The courses, the projects, even the certifications." Donor-supported nonprofit.
Ages 13–19 Coding
Exercism
8,500+ exercises across 83 languages — with free human mentoring: volunteers actually review your code, which nothing else on this list offers.
What’s free: "100% free, forever" (nonprofit); the paid tier is a donor thank-you, not a feature gate.
Ages 13–19, once you know basic syntax Coding
Codewars
Gamified "kata" challenges with martial-arts ranks; after each solve you see other people's solutions — that compare-and-learn loop is the real value.
What’s free: The kata library, ranks, and leaderboards (the paid subscription is ignorable extras).
Ages 13–19 Coding
MIT OpenCourseWare — Intro to CS with Python (6.100L)
The actual MIT intro course — full lecture videos, notes, and problem sets, explicitly aimed at students with little to no programming experience.
What’s free: Everything, no strings, no account.
Ages 15–19, strong students — it moves fast Coding
MDN Learn Web Development
Mozilla's structured beginner curriculum for HTML, CSS, and JavaScript — plus the industry-reference docs students will use for the rest of their careers.
What’s free: Entirely free, no account, no ads, no upsold certificates.
Ages 13–19 Coding
CS Unplugged
Computer science without computers — cards, string, and running around to teach binary, sorting, and error correction.
What’s free: All printables and lessons, Creative Commons.
Ages 11–13 (it's primary-leaning) Coding
CS Field Guide
An interactive online CS textbook written for high schoolers — algorithms, data representation, encryption, AI, human-computer interaction.
What’s free: Open source, fully free.
Ages 14–18 — the natural step up from CS Unplugged Coding
roadmap.sh
Community-built visual roadmaps (frontend, backend, Python, AI engineer…) that answer "what should I learn next?" — a map, not a course.
What’s free: All roadmaps and guides.
Ages 14–19, once you've started coding Coding
LeetCode (free tier)
Interview-style algorithm and data-structure problems. Only relevant for older teens targeting competitive programming or CS-admissions portfolios.
What’s free: 1,600+ of its problems with discussion forums; Premium is for job-hunters, teens don't need it.
Ages 16–19, advanced Both
YouTube worth a teen’s time (math edition)
For coding YouTube — freeCodeCamp, Fireship, Traversy Media, Tech With Tim — see our AI-assisted coding page.
Numberphile
Real mathematicians telling weird, delightful number stories. Zero prerequisites — pure curiosity fuel.
What’s free: Free; very active (uploading weekly as of July 2026).
Ages 11–19 Math
Mathologer
Deep visual proofs — why formulas are true, not just what they are. More rigorous than Numberphile.
What’s free: Free; active at a slow cadence (a few videos a year).
Ages 14–19 Math
blackpenredpen
Calculus and algebra problems worked marker-on-whiteboard in real time — the closest thing to a free calc tutor, ideal for AP students.
What’s free: Free; very active.
Ages 15–19 Math
What we checked and rejected (July 2026)
- Brilliant — heavily advertised as if free, but the free tier is course previews and a few daily “keys” that run out fast; actually completing any course requires Premium at roughly $28/month. A classic freemium trap — we don’t list it as a free resource.
- W3Schools — not paywalled, but passed over deliberately: ad-supported, sells paid certificates of little value, and its reference quality is a tier below MDN, which covers the same ground with a real curriculum.
- Khan Academy’s legacy JavaScript courses — still online, but superseded by their new Python intro; start there instead.