★ Exam prep — by examiners, for exam students

Learn Beyond Borders

Video lessons, classified past papers, study notes and direct teacher Q&A — mapped subtopic-by-subtopic to IGCSE, A-Level, SAT, AP and IB.

Browse courses→

∑

IGCSE & A-LevelCambridge O-Level · Edexcel

Soon

⚛

SAT & College BoardDigital SAT · AP

Soon

∫

IBSL & HL subjects

Soon

Mapped to the syllabus

Bite-size video lessons

Ask your teacher

Built around the official exam boards

Cambridge

Edexcel

College Board

IBO

Explore courses

Choose your exam system

Three systems, every subject mapped to the official syllabus. Pick yours to see its courses.

IGCSE & A-Level

Cambridge · Edexcel

Coming soon

O-Level: Math, Physics, Chemistry, Biology
Edexcel A-Level Math by unit (P1–P4, M1, S1)
AS & A2 sciences

Coming soon

SAT & College Board

Digital SAT · AP

Coming soon

Digital SAT — Math & English
Year-round rolling enrollment
AP: Microeconomics, Precalculus, CS

Coming soon

IB

SL & HL · sold separately

Coming soon

Math AA & AI (SL)
Biology, Chemistry, Physics (SL/HL)
Business Management (SL/HL)

Coming soon

Inside every course

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.

Paid add-on · Ask a Teacher

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.

Explore Q&A See pricing

Buy questions in packs — from $20 for 20 questions

✓

Verified Semestr teacher

Anonymous · usually replies within 24h

YouIn Q4 part (b), why does the sign flip?

✓Verified teacherBecause the limits are reversed when you substitute — flip them and the negative cancels.📎 worked-solution.png

Simple pricing

Pay only for the subject you need.

Buy individual courses — pricing varies by subject and level. Access is tied to your exam session.

All 5 package services
Classified past papers (3 formats)
Access through your exam window

Coming soon

Course pricing will be available soon

See course prices

How access works

🔓You enrollInstant, full access to everything.

📚Through your exam sessionStudy every topic and paper, the whole period.

🏁Ends after the examResitting later? Re-enroll for the next session.

ℹ️ Digital SAT is the exception — year-round rolling enrollment, with no session lock.

Common questions

Each course is bought individually at one global price, tied to your exam session window.

Subject to unit to topic to subtopic, following the official syllabus. Every subtopic has its own learning material.

Questions may be available unsolved, solved in writing, and solved on video.

Submit a ticket and a verified teacher replies within the published response time.

No — each unit is sold as its own course so you buy only what you sit.

Ready to start?

Pick your subject and get every lesson, the notes, the classified past papers and teacher Q&A in one place

Browse courses →