Math Topics

20,000 Problems Under the Sea

The site contains exactly 20,000 problems from 38 journals and 21 contests, all published before 1990. Solutions are not included unless they've been entered as online comments. However, references to published solutions usually are included, so if you can get to a good library, you can probably get to a solution.

Magic Stars, Squares and Other

This site has sections on magic squares, magic stars and miscellaneous number patterns. A large section provides a complete history of magic cubes. It also covers the wide variety and presents the many recent advances made in magic cubes.

You can find magic and multimagic squares and other magic shapes (cubes, hypercubes, ...) on this site. It it also in French and in German.