This simple but very addictive game will help you practice your mental counting and improve your reaction speed. The task is elementary. You need to choose whether the answer in the example is correct. Numbers are two-digit. Actions – addition and subtraction. It seemed impossible to lose. But the time limit and rather confusing tasks unsettle even someone who is very good at counting. The game is suitable for both schoolchildren who are learning the basics, and adult uncles and aunts. So, everyone who loves mathematics, quickly sit down on the screens and show the highest class. Just remember, you have no room for error. Good luck!