Calculus Master

The goal of the game is to find all possible variants of addition of the target number.
At each level will be presented its target number, the amount of which must be determined from the options presented in 12 cells. Do not yawn, for all this is definitely time. Also you have only 3 rights to make a mistake.
After passing through all levels, your counting level in the mind will go off scale!
Do not be cunning - use a calculator is not recommended;)