Harvey Mudd College
Mudd Math Fun Facts: Squares Ending in 5
This math tutorial features an exercise in which you are given any two-digit number that ends in 5 and then square it in your head.
Harvey Mudd College
Mudd Math Fun Facts: Magic Squares, Indeed!
This tutorial provides a definition and examples of a "magic square" and then shows a proof and generalizations.
University of Cambridge
University of Cambridge: Nrich: Four Triangles Puzzle
Sharpen your logic and and pattern recognition skills with this four triangles puzzle. The solution is available to check your work.
Discovery Education
Discovery Education: Puzzlemaker
At this site create your own puzzles, build your own maze and print them out for yourself or others to enjoy.
National Council of Teachers of Mathematics
The Math Forum: Increasing Wall Area
This site presents a problem at a museum that has one large square gallery. The director wants to divide this room down the middle into four smaller square rooms.
University of Cambridge
University of Cambridge: Nrich: 1, 2, 3 Magic Square
Sharpen your logic and basic addition facts skills while working on this challenge. Solution.
Other
Websudoku
A fun puzzler to get any mind thinking logically! Try many levels of puzzles using the following rules: "Enter digits from 1 to 9 into the blank spaces. Every row must contain one of each digit. So must every column, as must every 3x3...