How to play 21 Classroom game?
Each person must start with the number after the last one that the other person said. If the first person says 1, 2, then the second person could say 3 or 3, 4”. Whoever says 21 wins the game. Play this game many times and try to discover a winning strategy. It can help to write all of the numbers from 1 to the ending number and then circle the winning numbers. The winning numbers for the original counting to 20 game are 4, 8, 12, 16, and 20 itself. It is usually easiest to discover that 16 is a winning number first and then work backwards to find the rest.