Mental arithmetic training application.
If you win 10 games in a row, you will go to the next level.
level1 : 20x3, 20x8, ...
level2 : 21x2, 21x6, ...
level3 : 22x4, 22x7, ...
level4 : 23x5, 23x9, ...
level5 : 24x1, 24x6, ...
level6 : 25x2, 25x8, ...
level7 : 26x4, 26x7, ...
level8 : 27x3, 27x6, ...
level9 : 28x5, 28x9, ...
level10 : 29x2, 29x8, ...
In Japan, 8-9 years old (3rd grade)