How to play Single Digits. Object of the game is to make 24. You can add, subtract, multiply and divide. Use all four numbers on a card, but use each number only once. There is at least one solution to every card. 96 double-sided ards. 1 Dot, 2 Dot & 3 Dot cards provide three levels of difficulty - 1 Dot cards are easy, 2 Dot cards are medium and 3 Dot cards are tough. For ages 9 and up.