Plus & Minus is a simple game. It is all about doing quick math operations. Once you start the game you will find an equation falls slowly from the sky! It has three random numbers, one of them is unknown. You should solve the equation and find the unknown value before the equation falls down. You can use two kind of weapons for help:

Fire: use this weapon when you feel that you can not solve the equation, and you want to change the equation with different new random numbers.

Ice: use this weapon when you feel that you can solve the equation, but just need a little more time to find the answer.

That's all, be ready to test your skills!

Oh .. there is a free version of this game. You can try it if you like.