Keep the class on their toes and doing mental computation in these fast-paced games! Each card has a large "I have" numeral along with addition and subtraction questions at four levels of difficulty. One student reads, "I have 8. Who has 16 plus 5?" Be alert! If you have 21, it's your turn! Questions and answers continue until the cycle is complete. Includes 32 cards with answers from 1 to 32. Set A highlights basic addition and subtraction facts and beyond. Set B has simple column addition plus double-digit addition and subtraction with renaming. For the whole class, small groups, or as solitaire.