SUMUS is a game where your math skills and intelligence will be challenged. Its mechanic is easy to understand, but hard to master.From the upper part of the screen, randomly numbered (from 0 to 9) stones will fall. Your main goal is to pile up THREE stones in order to sum 13.They will fall faster and more often as you reach higher levels.You can tap a falling stone to "select" it. While a "selected" stone is falling, you will see the shape of that stone in all the avalaible locations where it could be placed. Tap one of the shapes to finally place the selected stone.To help you with this task, there are some special stones, called BONUS, with useful effects that have to be used wisely to get the most benefit from them.