Official blurb: Addition, subtraction, multiplication, and division all come into play. The first Player places from two to six numbered tiles on the board in ascending or descending order. Sound easy? Certainly-except that the total of all the tiles must be divisible by three. From here on, the action is fast and furious as each player builds numbers on numbers, trying to take advantage of bonus squares that can send your score soaring. Partner play will keep spirits high for a whole evening's entertainment. [Numble has a very similar board layout and play structure to Scrabble, save that you are working with numbers and basic mathematics.] - BoardGameGeek