An interactive program in which you build patterns on a triangular grid with pattern blocks. The main purpose is an introduction to fractions, but you could also build symmetric patterns. The Abacus A working Japanese abacus, with text explaining how it works. DuPage Children's Museum Home Page Math puzzles for younger kids. Mad Math Minutes for Web Interactive drill program for arithmetic.
Gives score and correct answers.
Multiple difficulty levels. For Middle School Interactive Mathematics Miscellany and Puzzles A big collection of interactive puzzles and and activities. Also a section on the Pythagorean Theorem, with many proofs, some interactive. SimCalc A simulator for various kinds of experiments with motion, involving distance, time, velocity, and acceleration. Not interactive, but you can download the program.