Contribute

Review the mathematics

This is the most valuable contribution of all. No lesson has yet been reviewed by a human mathematician. A review means reading a lesson or trail carefully and checking:

• definitions and theorem statements are correct and complete, with no hidden assumptions;
• every human proof is valid, and boundary cases are handled;
• historical and attribution claims are accurate;
• analogies are labelled as analogies and never confused with formal constructions.

Please open an issue with the lesson's identifier (for example math.found.sets) and your findings. Reviews are recorded with the reviewer's name and the date, and only then does a lesson earn the Mathematically reviewed label.

Review the teaching

Teachers, parents and education researchers can help by checking age-appropriateness, clarity, exercise difficulty, accessibility, and whether a lesson ever demands more than its prerequisites. A completed review earns the Pedagogically reviewed label.

Translate — or review a translation

The interface currently has machine-drafted translations in Spanish, Arabic, Hindi, Simplified Chinese and Swahili, and the first lesson has machine-drafted translations too. None has been reviewed. If you are fluent in one of these languages — especially if you teach mathematics in it — reviewing a draft is enormously helpful.

Every translation records the canonical English source it was made from (a short hash), so the site can warn readers when the original has changed. Definitions, theorems, proofs, exercises and mathematical terminology require review by someone who knows the mathematics as well as the language. The full workflow is described in docs/i18n/translation-workflow.md in the repository.

Write software

The site is a static Next.js application in TypeScript. Formal proofs live in formal/ (Lean 4), computational experiments in compute/ (Python), and all curriculum content in content/. To work on it locally:

npm install
npm run verify:lean     # compile the Lean library and write the verification report
npm run verify:compute  # run and test the Python experiments
npm test                # validate content, graph and registries
npm run dev

Contributions should keep the site fast, accessible, and usable on inexpensive devices with slow connections. Learner code must only ever run in the learner's own browser sandbox — never on a server.

Share feedback

If something is confusing, wrong, inaccessible or unwelcoming, we want to know. Clear, kind, specific feedback — "this step in the proof skips a case", "this example assumes a currency most of the world doesn't use" — is a gift.

Ground rules

Be truthful, be kind, and be precise. Respect learners and contributors of every country, culture and belief. Never claim a review, test or translation that did not happen.