2 problems from IMO, each rated for difficulty. Solve one to open its discussion.
The International Mathematical Olympiad (IMO) is the World Championship Mathematics Competition for High School students and is held annually in a different country. The first IMO was held in 1959 in Romania, with 7 countries participating. It has gradually expanded to over 100 countries from 5 continents. The IMO Board ensures that the competition takes place each year and that each host country observes the regulations and traditions of the IMO.
This page also carries problems from the IMO Shortlist and Longlist — the wider, still-official pools of candidate problems each year's IMO is chosen from. Each problem still says exactly where it's from in its source line.
A big portion of IMO problems involve proofs, something that isn't available in this website. As such, some of the problems featured here are modified to accommodate numeric answers which arguably significantly reduces the complexity of the problem.