You are the leader of the defenders of the city of Acron which is the last city on Earth that has not been destroyed by the alien invaders from Mars! The aliens are bombing all cities on Earth but you have figured out that if you can give the correct answer to some simple math equations and transmit them to the bombs before they hit the city then you can activate the bomb's self destruct mode and save your city. BUT be careful because the wrong answer can activate the bomb's accelerator engines and make them go faster. Also, if you destroy several bombs then the aliens will become angry and force the bombs to come quicker!