A+ Math Interactive math help for K-12 students with flashcards, Math Wordfind, Homework Helper and worksheets.
Colorful Mathematics 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.
Pythabacus Description and instruction of using the ancient Pythagorean Abacus to do arithmetic.
Mathwizz Interactive math problems for abilities ranging from middle school to university.
Archive Creative puzzles Interactive puzzle archive with descriptions for puzzle construction and a special childrens puzzle page.
MatheMagic A collection of mathematical puzzles, jokes and articles.
Mathschallenge.net A website dedicated to the puzzling world of mathematics, with a discussion forum.
Alphametics and Cryptarithms Puzzles in which letters or symbols are substituted for the digits in an arithmetical operation like addition.
Alphametics Page Compiled by Mike Keith. Examples of various genres.
Logic Puzzles 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.
Mathpuzzle.com Celebrates math puzzles and mathematical recreations.
Algebraic Math Puzzles A collection of puzzles at high school level. Does not include answers.
Free Puzzle Collections Educational and recreational puzzles for teachers, students and parents. Each puzzle is graded by difficulty and has a hint. Solutions are available to members.
Aha! Puzzles Puzzles, books, games and tests with designed by Lloyd King, author of "Test Your Creative Thinking".
The Little Math Puzzle 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.
Problem Solutions Archive of problems and solutions, compiled by Dr Alec Mihailovs of Shepherd College.
Mathematical Games A collection of pencil and paper games with mathematical content. Many can be played through the site.