Robols Math

Competition Maths practice usually means a PDF of problems and an answer key. Nothing tells you whether a problem was genuinely hard or whether you are improving, difficulty is one author's guess, and the moment you go looking for a hint the solution spoils the problem.

Robols Math is a rated archive for mathletes and enthusiasts. Every problem carries a rating on the same scale you do, both starting at 1000. Taking one on is a single game between you and the problem: beat a problem above your rating and you climb meaningfully, lose to one well below you and it costs a great deal. Ratings and XP are recalibrated daily.

What makes it different:

• Difficulty is measured, not asserted. A problem's rating blends the problem setter's estimate, how solvers actually fared on it, and difficulty votes from the people who beat it.
• Four leaderboards, not one. Rating, XP, problems solved and contributions are ranked separately, so giving back to the archive counts as its own kind of standing. Any row puts your record side by side with that solver's.
• Discussion opens only once you have finished. Solve a problem or give up on it and the thread unlocks, so nobody can spoil it for you.
• The archive is built by the people using it. Anyone can propose a problem. Accepted ones are credited to their author, and the proposer's own solution becomes the first comment.
• Warm-ups that cost nothing. Practice problems earn XP but leave your rating untouched, so you can drill fundamentals without risk.
• Badges you earn rather than collect. Twenty-six of them, worked out from your solving record rather than granted, so a badge always matches the numbers beside it.

Over 500 problems across nine categories, with proper LaTeX and diagrams. The archive grows daily and we expect to have at least a thousand problems by end of 2026. 

Website is free, nothing to install, works on a phone.