Workshop: Factors, Multiples, and Primes

Give students some time to solve the problem. Select a few students to share how they solved the problem. See Figure 6 for one possible strategy.

Tell students that John found one additional square tile. Ask students if John can make a rectangle with 61 tiles. Students will probably announce that John can make a 1 × 61 rectangle. Then ask if there are any other rectangles that he can make. Encourage students to share their strategies. Some students will skip count by 2, 3, 5, 7; others may try to build a rectangle or use a tool such as a multiplication chart to decide that 61 is a prime number.