Recreations
- 41
- Who Can Name the Bigger Number?
- An essay by Scott Aaronson on the quest for ever-bigger numbers, from exponentials to Busy Beavers.
- 42
- A Cleverly-Titled Logic Puzzle Blog
- A large and varied collection of puzzles by logicsmith Grant Fikes.
- 43
- Aha! Puzzles
- Puzzles, books, games and tests with designed by Lloyd King, author of "Test Your Creative Thinking".
- 47
- Alphametics and Cryptarithms
- Puzzles in which letters or symbols are substituted for the digits in an arithmetical operation like addition.
- 48
- Brain Teasers and Maths Puzzles
- Interactive logical and mathematical puzzles with feedback and detailed solutions.
- 50
- 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.
- 52
- Creative puzzles
- Interactive puzzle archive with descriptions for puzzle construction and a special children's puzzle page.
- 53
- Dick's Math Puzzle Page
- A collection of mathematical puzzles, some original, with fully worked solutions.
- 54
- 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.
- 57
- IQ Flash: Online games, puzzles
- New printable puzzles, math games, board games, and logic games in flash.