Mental arithmetic training application.
If you win 10 games in a row, you will go to the next level.
level1 : 30x4, 30x7, ...
level2 : 31x2, 31x9, ...
level3 : 32x1, 31x6, ...
level4 : 33x3, 33x8, ...
level5 : 34x5, 34x7, ...
level6 : 35x4, 35x6, ...
level7 : 36x3, 36x9, ...
level8 : 37x1, 37x8, ...
level9 : 38x2, 38x5, ...
level10 : 39x4, 39x7, ...
In Japan, 8-9 years old (3rd grade)