Unpacking the question bank…
Are you sure? Give it another thought first. Revealing this hint will mark it as used.
A small guide to the climb.
Every IMO competition question from 1959 to 2026. Pick any year, or start at the top of the list.
1a is easiest; 3c is hardest. Grades use contestants’ full-mark rates. Within each level, a, b and c are the easiest, middle and hardest thirds. Plain numbers (e.g. 1) are used where contestants marks are unavailable.
Some questions have three hints, each more revealing. Try on paper first; use a hint if you get stuck. More hints are coming.
Start an attempt, save a reminder, and pick up where you left off. Mark it solved when you’re done. Your notes stay private.