Swipe numbers next to each other in any direction to make a total of 21 and to remove them of the board.
Each number can be used only once. Score for each move is higher if you use more numbers.
To be able to compress empty space and to have a chance to get into bonus rounds you need to remove all anchors (blue numbers).
Each move must equal exactly 21 and to include no more than 1 anchor number (0 anchors is permitted).
Remove all anchors and get over 2950 points and you get into bonus rounds. Each round unlocks 10 more numbers and 1 more minute of gameplay plus 1 wild number that can be used for any number between 1 and 9.
Master the strategy and you will master the board! However, keep swiping 21 your every move!