Paired

Get the number on the title bar, pressing 2 keys.
If your addition, subtraction or multiplication you get it, you score and you keep playing.
Lose lives if you exhaust the time or if there are no more combinations.
Every time you hit, the timer is reset.
Every time you lose a life, a new number is generated.

Example: Title bar number is 12

(1,12), (6,6), (6,2), (14,2), (4,3), (8,4)
(7,5), (13,1), (15,3), (16,4), (9,3)...