A nice and different kind of calculation app. Beware: there is the aspect of fighting in this app.
Math Ninja is an app to practice calculation. In this app, the kid is a math ninja. As a math ninja, kids have to defend their tree house against Tomato-San, who envies math ninja, because he's not as good as him in math. To annoy math ninja Tomato-San will invent new monsters, to find out what treasure, math ninja is hiding. He tells this in a little story at the beginning of each level. To defend the tree house, kids have different weapons, which they can buy and enhance. To be able to buy them, kids have to solve arithmetic problems twice in one level. Before you start a game, you can choose from three levels of difficulty. With each level the monsters as well as the arithmetic problems will get more difficult. Furthermore, you can choose the calculation type. Either you take all four - addition, subtraction, multiplication, and division - or you choose one of them. This makes it also possible for first graders to use the app.