Drop the numbers into the colored boxes such that the sum of the numbers equals the required number for each box. The levels start off easy but later levels can be very tough. See if you can use your addition and thinking skills to complete all 60 levels.......without using the solutions button on the main menu too much!
Drag and drop the letters using either touch or the mouse. In-game instructions on starting levels show you how to play. Be sure and click the number boxes at top if you need to highlight a box. On later levels, when more boxes intersect, it helps to make the box boundaries easier to see.