A+ Math - - Interactive math help for K-12 students with flashcards, Math Wordfind, Homework Helper and worksheets.
Aha! Puzzles - - Puzzles, books, games and tests with designed by Lloyd King, author of "Test Your Creative Thinking".
AIMS Puzzle Corner - - Provides over 100 puzzles with the goal of creating an engaging learning environment.
Algebraic Math Puzzles - - A collection of puzzles at high school level. Does not include answers.
Alien Tiles - - Object of puzzle is to try to get color pieces to create certain patterns in cube.
Alphametic Puzzles - - Numerous puzzles, links, puzzle solver, and a generator.
Alphametics Page - - Compiled by Mike Keith. Examples of various genres.
Ben Robinson's Cross-Number Puzzles - - A collection of cross-number puzzles: similar to crosswords, but using digits instead of letters. Many involve complex mathematical reasoning.
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.
The Contest Center - - Classic puzzles and riddles requiring only simple logic and elementary math.
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.
Group Games - - Animations that develop the theory behind such puzzles as the Rubik cube.
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.
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.
Logicville - - Educational puzzles, brain teasers, and word games such as anagrams, cryptograms, alphametics, doublets, tangrams.
Magic Math Kingdom - - Learn math through games and quiz-oriented tutorial.
Math Puzzles - - Logic puzzles and riddles with some solutions.
MatheMagic - - A collection of mathematical puzzles, jokes and articles.
MatheMajik - - Indian site featuring calculation tricks and math puzzles.
Mathematical Games - - A collection of pencil and paper games with mathematical content. Many can be played through the site.
Nick's Mathematical Puzzles - - A collection of puzzles, with hints, solutions, and links to related mathematical topics.
Paul Hsieh's Puzzles - - Logical and mathematical brain teasers, with an indication of difficulty. Hints are provided; solutions are available by email.
Perfect Times - - Teaches and assesses fluency of multiplication and division tables using online cards. Submit data and compare results.
Polyhedra Links - - Pastime and activity links for various geometric patterns, polygons and polyhedra by Jill Britton.
Polymorf - Symmetry of Polyhedra - - A demonstration of the symmetry and transformational properties of the Platonic and Archimedean solids.
15 Puzzle of Sam Lloyd - - Play online Sam Lloyd's "15" puzzle. The funny story and mathematical implications of this game. Some funny logical problems with the 15 game.
Puzzle of the Week Archives - - A collection of puzzles, with hints and full solutions. Compiled by George Moody.
Puzzles of Leonid Mochalov - - A variety of challenging geometrical and arithmetical puzzles, many with solutions.