ALIEN ADDITION Arcademics© - Math Space Invaders, the free online math game that combines addition calculations with the spaceship game "Space Invaders". Arcademics game, Alien Addition. Add two digits up to 20 as a result, position the laser cannon using the arrow keys and shoot (using the space bar or the up arrow) at the alien ship containing the numerical solution of the addition. Choose the speed of the game, so that the ships approach sooner, and you have to add faster. Review the sums made in order to highlight the mistakes made by the children learning to add, and improve their learning of the sums.