Free Learn
Full course hubs that teach college material properly — not just formula lists. Each lesson covers one formula: where it comes from, the full derivation, how to use it, worked examples with common-mistake callouts, and quizzes interleaved through the page. Finish with unit tests and a final exam; your progress is tracked in your browser.
Calculus I — Complete Course
The complete Calculus I course: 71 bite-size formula lessons, interleaved quizzes, 5 unit tests, and a 40-question final exam — with progress tracking.
Start learning → LivePhysics I — Complete Course
The complete Physics I: Mechanics course: 59 formula lessons, unit quizzes, and a final exam covering kinematics, forces, energy, momentum, and rotation.
Start learning → LiveProduct rule
Master the product rule: full derivation from the limit definition, 4 worked examples, and interleaved quizzes.
Start learning → LiveTime-free equation
The time-free kinematic equation v² = v₀² + 2aΔx: where it comes from and how to use it, with quizzes.
Start learning → LiveIdeal gas law
The ideal gas law, PV = nRT, explained: derivation, unit handling, and worked examples with quizzes.
Start learning → LiveBayes' theorem
Bayes' theorem from the ground up: intuition, derivation, and worked examples with quizzes.
Start learning → LiveEigen-equation
The eigen-equation Av = λv: what eigenvalues and eigenvectors mean, with worked examples and quizzes.
Start learning →Related categories
More from the codex
Browse all categories
Every category on the codex, from study tools to ciphers — pick your starting point.
Browse → LivePrompt Simulator
Practice prompt engineering: write prompts, get scored 0–10.
Open tool → LiveGPA Calculator
Semester and cumulative GPA with weighted scales and a target planner.
Open tool →About these learn
Every tool below is free, works in your browser, and needs no account.
- How do the course hubs work?
- Pick a course, work through its lessons in order (each links its prerequisites), take the unit quizzes as you go, then sit the final exam. Missed questions link back to the lesson they came from.
- Is my progress saved?
- Yes — lessons you mark as learned and quizzes you attempt are saved in your browser, and each hub shows a progress bar. Nothing is sent to any server.
- Which courses are available?
- Calculus I and Physics I are complete. More courses unlock as their lessons are written — each follows the same lesson + quiz + exam structure.
Like these tools?
The Magic Codex is built by an independent developer. If these free tools saved you time, consider supporting future ones.
Donate