In Sum the aim is to collect a specific sum in each of the four different levels, either 5, 10, 20 or 30. Drag you finger over the numbers in order to add up the chosen sum. Remember to be precise, because if you do not get the correct sum you will start spreading red color. To remove the red color you have to start counting on a white box, and then keep counting through the red boxes. If you see a bomb, you can collect it by dragging over it when you make a sum. To use a bomb, select it from the collected bombs and drag it to an area to remove the red boxes. The game ends when everything turns red.