Gotcha is one of the cool math games that we use at teachwithgames.com to help students memorize their multiplication tables (and other sequences). It is similar to Solitaire, just with friends. I made a video to show how to play if you find the included rules unclear.
Teachwith games.com now has over 100 kids learning games for you to use to help your student memorize part of the vast amount of information that is required in our world today.