If a simple mathematical operation you have never had any difficulties, so with this game in the shape test your reaction and mental abilities difficulties should arise. The rules are simple - you are, and have your opponent with whom you fight a duel in the brain so to speak. And this fight is a next - you need to quickly make operations like addition and subtraction, and your opponent. Whoever will result in more correct answers will be considered the winner. And after the battle will be to raise some of their skills. Mouse control. Enjoy the game!