The goal of this app is to learn abacus and calculate these questions by mental arithmetic within 5 seconds. All lessons of the abacus lesson series, which have been highly evaluated all over the world, are recorded. The lessons have been reworked in a more polite and easy-to-understand. In addition, we have added unique training methods such as training focusing on finger movements and mental arithmetic training to improve mental arithmetic in order to learn abacus more efficiently. And various