# How to play

The first thing you need to do when playing our math games is pick a difficulty level. Kids that are just learning to subtract should try the beginner level. Adults who are already very good with arithmetic should try the Advanced or Impossible difficulties. When you play the easier difficulties, the aliens attack at a slower rate, and the math problems you must solve to zap them are much easier than on the higher levels. If you are already really good with Math, you can play the Impossible difficulty to see exactly how good you are.

After you choose a difficulty, aliens will begin to attack from above the game screen. Each alien will have a math problem above them you must try to solve.

When you know the answer to the math problem, type it on your keyboard. If the answer is correct you will zap the alien and your score will go up.

If you don't answer the math problem correctly you will get an error message and your score will go down. If you take too long to answer the math problem, the aliens will begin to bomb your city. If your city is destroyed you lose the game.