Addition is an application within the time limit to the number being displayed.
The display is five digits.
Addition to which it is OK.
The high scores to compute the five numbers at once.
Correct time to recover.
And completes the top left there is no time bar.
There are three difficulty.
Easy - two digits
Normal - 3 digits
Hard - 4 digit
YouTube:
http://youtu.be/c59yVXYaA1o