Numbers fall from the top of the game area and you can move them side to side using the left and right arrow keys. If you decide to disgard a number, you simply move it all the way to the right or the left of the game area so that it can fall through the gutter. Otherwise, it will land above a target number between 10 and 16. To score you make number fall on another number which is already positioned above a target number so that the sum of the two numbers equals the target number. You get one point for sums of 10, 11, and 12, two points for sums of 13 and 14, and three points for sums of 15 and 16. When you reach a score of 20 the game is over. The real "score" you should pay attention to is the total bricks used. You want to reach 20 while using as few bricks as possible. A score under 40 is real good.
Game area at start of game.
Game area after several numbers are positioned above target numbers.
Game area with a second number in position to score. (8 + 8 = 16, this move is worth three points!)