24 Game: Add/Subtract Primer players have one goal: to make the number 24 from four numbers on a game card by adding, subtracting, multiplying, and dividing - -using each number only once. Add/Subtract Primer cards incorporate positive numbers only. Cards offer three levels of difficulty coded by dots: "1 Dot" cards are easy, "2 Dot" cards are at a mid-difficulty level and "3 Dot" cards are tough. Game cards are 4'' x 4'' and double-sided. 48 cards. Ages 6 & up.