Where the problems come from
Maths Olympiad Prep did not write these problems. They belong to the competitions and mathematicians who created them, and reach this site through the three open datasets below. Our work is in turning that material into something you can train on: identifying duplicates, classifying topics, estimating difficulty and building the sequence.
The datasets
MathNet
Official problem booklets from 43 countries, 1989–2026, with expert solutions. Licensed CC BY 4.0. Dataset.
Omni-MATH
Olympiad-level problems carrying human difficulty ratings, which this site used to calibrate its own scale. Licensed Apache 2.0. Dataset.
NuminaMath 1.5
Competition problems collected from exam papers and mathematics forums. Licensed Apache 2.0. Dataset.
What this site added
Statements and solutions appear as published. We added the metadata: a topic for each problem, a difficulty rating, deduplication across the three sources, and the order. Every problem page names its own source and licence.
On the problems themselves
Those licences cover redistributing the collections. They don't cover authorship of the problems, which sits with the competitions named on each page. So the problems and solutions here are free and will stay free. If this site ever charges, it'll be for the ordering and the tracking, not for the problems. If you set one of these competitions and want a problem taken down, ask and it comes down.