Use your ninja instincts and arithmetic to defeat numbered foes in Number Ninjas! In each stage, you are presented with an equation, which is displayed in the top left-hand corner of the screen. You'll have to carry out the equation by picking up subtraction, addition, multiplication and division shurikens, and then throwing them at enemy numbers. Once the equation is solved, it will turn green, and you can move to the flag to finish the level.