The board has a matrix of 10x10 tiles on which a number between 0 to 9 is placed on each of the 100 tiles. Tiles with 0 on it are colored green and tiles with 1 to 9 on it are colored dark blue. Green tiles cannot be moved. Any dark blue tile on board can be moved to another dark blue tile immediately above, below, left & right by dragging the tile with mouse if the number on source tile is less than or equal to the number on destination tile. After moving the tile the number on source tile gets set to 0 and number of destination tile gets set to unit digit of a number which is sum of source & destination tile. Eg - If 2 is moved to 4, the tiles gets changed to 0 & 6. If 7 is moved to 8, the tiles get changed to 0 & 5(unit digit of 7+8). If 5 is moved to 5 both the tiles get changed to 0. The color of tile with 0 digit on it changes from dark blue to light blue and the tile cannot be moved further. Any tile which has a light blue tile with a 0 digit on all four sides (immediate left, right, top, bottom) cannot be moved as the number on that tile is greater than 0 and is painted red. The aim of game is to convert all dark blue tiles to light blue or red tiles and game ends when there are no dark blue tiles. The lesser the number of red tiles on board the higher the score.