Mental arithmetic training application.
If you win 10 games in a row, you will go to the next level.
level1 : 12+5, 13+2, ...
level2 : 20+3, 20+7, ...
level3 : 21+4, 26+3, ...
level4 : 30+2, 30+5, ...
level5 : 34+1, 36+2, ...
level6 : 50+3, 80+9, ...
level7 : 42+6, 75+2, ...
level8 : 20+10, 50+10, ...
level9 : 30+20, 60+20, ...
level10 : 40+50, 20+60, ...
In Japan, 6-7 years old (1st grade)