CardMath

From the company's Website:

The primary objective of CardMath is to use numbered cards (Math Cards) and Operator Cards (+ , -, x, ÷) to create an equation whose result is selected as the target. Players collect as many Math Cards as possible (each card has a point value printed in the center). The secondary objective is to use up all of your Math Cards before the other players can use up all of theirs. Once a player uses all of his or her cards, the game ends, and points are tallied. The player with the most points wins the game.

There are many ways to set this game up, to accommodate different levels of math skill of the players. The Spinner can be used in the center of the board to determine the target equation’s solution or it can be removed so that the target solution is always 21. Or, take away the multiplication and division operators, so that less skilled players only have to think about adding and subtracting. When math skills increase, CardMath will be along side to grow with your needs.