Video lessons, classified past papers, study notes and direct teacher Q&A — mapped subtopic-by-subtopic to IGCSE, A-Level, SAT, AP and IB.
Mapped to the syllabus
Bite-size video lessons
Ask your teacher
Built around the official exam boards
Choose your exam system
Three systems, every subject mapped to the official syllabus. Pick yours to see its courses.
IGCSE & A-Level
- O-Level: Math, Physics, Chemistry, Biology
- Edexcel A-Level Math by unit (P1–P4, M1, S1)
- AS & A2 sciences
SAT & College Board
- Digital SAT — Math & English
- Year-round rolling enrollment
- AP: Microeconomics, Precalculus, CS
IB
- Math AA & AI (SL)
- Biology, Chemistry, Physics (SL/HL)
- Business Management (SL/HL)
Six things you get with each subject
Video lessons by subtopic
Concise lessons broken down to the smallest syllabus unit.
Study notes by topic
Written notes to revise from before the exam.
Past papers — unsolved
Classified by topic so you drill exactly what you need.
Past papers — solved (written)
Full written model answers for every question.
Past papers — solved (video)
Per-question video walkthroughs of the mark scheme.
Q&A credits
Ask a real teacher when you're stuck — credits included with every course.
Stuck on a question? Ask a real teacher.
Subscribe to 1-to-1 Q&A for any subject — no course purchase needed. Send your question, a verified Semestr teacher answers within the SLA. Identities stay anonymous on both sides.
Buy questions in packs — from $20 for 20 questions
Common questions
Most of the curriculums will be available within the next year.
Yes. Every course has 2 full lessons you can watch for free, with no sign-up and no payment. You'll find them on each course page.
The video-solved classified past papers will be provided at the start of November.
They will be provided at the start of November.
Yes. Most of the curriculums will be available within the next year.
Ready to start?
Pick your subject and get every lesson, the notes, the classified past papers and teacher Q&A in one place
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