Human Calculator

The human calculator is a game of mental calculation in which you must solve as many arithmetic operations as you can in a row. The operations are addition, subtraction, multiplication and division, and each game will get more complicated as you solve operations.You can choose the difficulty level, which depends on the time you have to solve each operation.The game uses Google Games Services, which will allow you to compare your scores with your friends and compete with them.Please, take a time to rate the game, an tell us what to do to improve it. Thanks!