Colorful MathematicsSave
Educational software presents advanced mathematics to K-12 students in a game-oriented approach, using coloring and drawing techniques to illustrate concepts from graph theory and computer science. http://www.math.ucalgary.ca/~laf/colo...
Free Puzzle CollectionsSave
Educational and recreational puzzles for teachers, students and parents. Each puzzle is graded by difficulty and has a hint. Solutions are available to members. http://www.freepuzzles.com/
Logic PuzzlesSave
Collection of original numerical-logic puzzles. Many are long and difficult, involve sorting and comparing long lists and are intended to be solved using a good spreadsheet program. http://www.geocities.com/bob_kraus_2000/
The Little Math PuzzleSave
The Little Math Puzzle has been a K-12 Internet activity since 1995 for grades 5-9. Currently the puzzles have ceased but the site maintains complete archives of past problems. http://www.sprucelog.com/lmp/