NCTM – Illuminations

This website is powered by the National Council of Teachers of Mathematics. It includes Great brainteasers that have PDF downloads for the question and the answer.

University of Cambridge

This website is out of Cambridge, England, and has games divided out for students in K-5.

United States Mint

Are you interested in this history of money? Would you like to know where our money comes from when it’s brand new? Visit the United States Mint. Check out the games, cartoons, and time machine of coin mysteries!

XtraMath

This website is great for practicing those difficult math facts. It tracks your progress each time you log in and also tells you which facts you have mastered, and the facts you need to work on.