For teachers
1,964 olympiad problems in a deliberate order, from AMC 10 level to the IMO shortlist, every one with a worked solution and a difficulty that was measured rather than guessed. Another 12,849 sit in a searchable library covering 230 competitions. It is free, there are no ads, and a pupil needs no account to use any of it.
Using it with a class
A class at mixed levels
Send everyone the placement test. It is twelve adaptive questions and takes about twenty minutes with pen and paper. Each pupil comes out with a stage and a place to start, so the strongest are not repeating what they can already do and the rest are not staring at something hopeless.
The placement testOne pupil who has run out of road
Pick the goal they are aiming at and hand them the route. Each one says how many problems it holds and how many hours a week it takes, so the commitment is clear before they start rather than three months in.
The five routesA weekly club or enrichment hour
Work down a stage in order. The topics rotate deliberately, so no two weeks running are the same kind of problem, and the difficulty climbs slowly enough that the group stays together.
The eight stagesHomework, cover or a booklet
40 printable sets, ten problems to a sheet, one stage and one topic, with the answer key on its own page at the end. Nothing to sign up for and nothing to install — they print straight from the browser.
Printable setsWhat your pupils will see
- No cost and no ads. There is nothing to buy and nothing is sold.
- No sign-up. Every problem, solution and printable set works signed out. An account only saves someone's place across devices.
- If they do make one, we store an email address and which problems they have attempted. Nothing else, and nothing is passed on.
- Answers are checked as they type at the lower stages. From stage 6 most problems want a proof, so they read the official solution and mark themselves — a browser cannot grade a proof and we do not pretend otherwise.
- Every problem has a worked solution from whoever published it, so nobody gets permanently stuck.
Where the problems come from
Official competition booklets from 47 countries, international shortlists and two large open datasets. Every problem page names the competition it came from, the dataset that published it and the licence. The problems belong to the people who set them, not to us, and they will stay free.
Honest limits
There is no class dashboard yet, so you cannot see who has done what from your own account. Stage 10 is ordered by rank rather than against a fixed standard, because nothing in the source data records which shortlist problems were the hardest. And the hour estimates are estimates: some problems fall in minutes and some ruin an evening.