Add 'em Up’s gameplay is based on a simple concept. You are given a board of random digits (between 0 and 9), and you have to clear the board. How do you do that? You pull tiles off of your queue on the right and place them on the board. It and all of the tiles it touches clear if those other tiles add up to the number you just placed (or if the sum of those numbers is two digits -- then the number in the one’s place has to equal the tile you just placed). For example, if I have a 5 that I need to place, then I can put it on the board next to a 3-tile and a 2-tile, or a 9-tile, 4-tile, and a 2-tile because they (9, 4, and 2) sum up to 15 and the number ends in 5 and all of those tiles will disappear.
In each level, you get six special moves. You can choose to blow up an entire area, remove all tiles of a certain number, reload your pending queue so that you have a new set of random numbers to use, randomly change all of the remaining tiles, or undo the last move.
Classic Mode challenges you to clear the board within a certain number of moves. Your score is based off of the number of tiles you clear per placement and the number of moves it took you to clear the board. Practice Mode is just like Classic Mode, except you don’t have to worry about score, number of moves, or anything like that. Here you can refine your skills and strategies at your own pace. Panic Mode pits you against the clock as you try to clear the board in less time than the current high score holder. Puzzle Mode puts the initial tiles in specific patterns, and allows you to only place tiles in certain places. And on top of all that, you are given a limited number of each tile.