Organization that sponsors the Canadian Open Mathematics Challenge, the Euclid Contest, the Gauss Contest, with online workshop, problem archives, and other resources for students.
Math olympiads for Polish high school students. Features problem archives from the Austrian-Polish Mathematics Competition, Baltic Team Contest, Poland Mathematical Olympiad.
Information and resources for the Putnam and the UIUC Undergraduate Math Contest. Includes practice problems and solutions. Maintained by Professor A.J. Hildebrand.
Mathematical problem solving contest named after the world famous Norwegian mathematician Niels Henrik Abel. Includes contest problems in downloadable format.
Results from the Putnam competition, old exams, and problem archives. Includes problem of the day, selected from over 540 different Putnam, National or International Olympiad problems.
Organization that administers the AMC, the AIME, and the USAMO, with information about the contests, math problem archives, recommended reading lists, and other resources for students interested in mathematics.