Mondo Math

Mondo Math is an arcade-style game which teaches arithmetic.

The object of the game is to clear the screen of all
objects and to accumulate points. Non-digit carrying objects
(which result from having hit a digit carrying object) can
be hit at any time, and simply disappear when hit. The gaps
left by hit objects make it increasingly easy to hit objects
on the second and top rows. The game ends if you run out of
bullets before clearing the screen of all numbered objects.