Mental arithmetic training application.
If you win 10 games in a row, you will go to the next level.
level1 : 130-10, 190-90, ...
level2 : 120-40, 140-50, ...
level3 : 162-2, 159-6, ...
level4 : 191-6, 136-9, ...
level5 : 183-62, 194-73, ...
level6 : 113-41, 118-62, ...
level7 : 196-68, 181-27, ...
level8 : 112-88, 131-98, ...
level9 : 200-3, 200-8, ...
level10 : 200-56, 200-73, ...
In Japan, 7-9 years old (2nd or 3rd grade)