Cost: .99 (Free version available, addition only)
Pairs of bubbles float on the screen and your goal is to pop each pair. Once you've popped all pairs on a level, you see your time for that level and can move on to the next level, or keep practicing that level. At any time, you can choose different operators: addition, subtraction, multiplication and division. New levels increase the numbers shown in the bubbles, up to 1000 for addition/subtraction and 20 for multiplication/division.