This game is a great way for students to practice using mental math on problems they have learned in class. Print out a set of cards (20 cards per set) and give one card per child. The game can begin with any child. For example, the first child will read their card, "I have 6. Who has this number plus 9?" The student whose card has the answer says, "I have 15. Who has this number minus 5?" The game continues on until the final person's answer loops around to the first card read. Enjoy!