This activity will help students to distinguish between good and bad strategies for playing the games that follow, and it encourages them to look again at what composite numbers and prime numbers are.
Review with the students how to name a set of factors for a number. For example, the factors for 10 are 5, 2, 10, and 1. Discuss why Stacey thinks that 17 will not give Laird a lot of points.

Game

In this game, students need to make mental estimations, think ahead, and identify factors and primes. High prime numbers give away the fewest points.
The game board is graded at three levels of challenge. Increase the challenge gradually. If the students are faced with too many numbers early on, they can easily get confused and begin to cover numbers randomly rather than thinking strategically.
Observe carefully and encourage the students to reflect on their choices if these are not particularly sound. You may need to remind the students that all uncovered factors must be covered and that some factors may already be covered and therefore will not be available.

Answers to Activity

None. The only factors of 17 are 17 and 1. Stacey has just covered 17, and the 1 was covered earlier in the game.
Game
A game using factors