Inspired by the arcade hit "whack-a-mole" this version delivers the same heart pumping action but with an educational twist. In order to actually "hit" the mole you not only have to whack it with your finger but you must answer a math question. "Math-a-Mole Subtraction" supports only Subtraction. The game starts with single digit math and ramps up to three digit arithmetic. If you want to quiz other math operations consider getting "Math-a-Mole Ultimate" instead for US$2.99 which includes addition, subtraction, multiplication and division. It is buy 3 and get 1 for free!!