Addition Brain Teaser - Very interesting math puzzle game for all players. You need to get the correct number, but you can only add equal numbers together or numbers whose sum equals a number already on the board. For example, you can add 4 and 4 together because they are equal. If 9 is on the board you can combine 6 and 3 together. Although 6 and 3 aren't equal their sum is 9 which is on the board. Have fun!