Numbervaders

Maths assignments fall from the sky, and it's your job to shoot them down by typing the correct answers. If a maths assignment lands, the game tells you the correct answer to that assignments, then you can just start over. You learn stuff! If you manage 20 assignments you advance to the next level, with harder questions and higher speed. After beating level 20 you'll have gone through 1x1 all the way up to 10x10.