About eXercise
eXercise is a free, bilingual English–Chinese study site for Cambridge IGCSE, Cambridge A-Level and AP. Everything on it is open to read without an account.
Bilingual by design
The site is written for students studying an English-language syllabus in Chinese-speaking schools. Difficult terms carry an inline Chinese gloss, and most pages have a full Chinese version — switch with the flag in the header. Code stays in English, because that is how it is written in the exam.
How the material is made
The notes and lessons are written by hand against the official syllabus and past papers, not generated in bulk. Diagrams are drawn for the page; photographs come from freely-licensed sources and every one is credited. Concept animations are rendered with Manim. Image credits.
What it costs
Reading, practising and running code are free and always will be. Features that call an AI model cost real money to run, so those have a free allowance and then run on prepaid credit at the exact provider price, with no markup.
Corrections and contact
If something is wrong — a mistake in the notes, a broken figure, a question marked incorrectly — use the feedback button in the corner of any page. It reaches us directly, and corrections to the material are the most useful thing you can send.