Interactive Mathematics Miscellany and Puzzles

This website is hosted by the Mathematical Association of America's MAA Online, for whom Mr. Bogomolny also writes a monthly column. The puzzles, which include such classics as Breaking Chocolate Bars and Latin Squares, are accompanied by enjoyable Java applets that let the user try out different solutions. The problems, which fall into the categories Arithmetic/Algebra, Geometry, and Probability, also make extensive use of applets. Both include discussions, sometimes quite extensive, of the relevant mathematics.

A collection of online movies illustrates procedures such as the making of a Klein bottle. Also useful is the CTK Exchange, in which Mr. Bogomolny provides answers to students' questions. This copious site is a must for math clubs, and could be a real boon for the classroom as well. Be sure to check out the 28 proofs of the Pythagorean Theorem!