The free app called Math Slicer gives students practice with math facts in any of the four operations. The concept is much like Fruit Ninja where the student uses a finger or stylus to “slice” through fruit earning points along the way. The only difference is that in this game, the student is slicing through the correct answer to the math equation. It is loads of fun and much more engaging than a worksheet or flashcards.
Note: There is also a paid version ($.99), but the link above will take you to the free option.