Brain training,math puzzlegame description

Arithmetic bubble is a brain training math game to complete the formula by selecting the sign and the number of bubble
And trying to complete a formula in time!

Six of difficulty
Practice classroom, Novice School, Intermediate School
Senior classroom, master classes, professional classroom
It is equipped with a ranking system in each classroom.

Let Kitaeyo the brain with brain training a little free time!

"How to Play"
1: ＋、ー、×、÷　Choose the sign
2: choose a number that was in the sign