Name Chapter 14, Lesson 3 Reteach Date Prime and Composite Numbers CA Standards NS 4.2, NS 4.1 You will find the factors of a prime number and the factors of a composite number. Step 1 To determine if a number is prime or composite, you can use counters to make arrays or you can use divisibility rules. Step 3 To determine if 6 is prime or composite, use counters. Step 2 To determine if 5 is prime or composite, use counters. With 6 counters, you can make several arrays. 6 is a composite number because it has more than 2 factors. These factors are 1, 2, 3 and 6. With 5 counters, you can make only one array. 5 is a prime number because it has only two factors. These factors are 1 and 5. 1×5=5 1×6=6 2×3=6 In the table below, list the factors for each number. Use counters if you wish. Tell if the number is prime or composite. Number 1. 13 2. 20 3. 31 4. 15 Factors Prime or Composite Writing Math Explain how you could use divisibility rules to determine if 39 is prime or composite. Reteach Use with text pages 306–307. Copyright © Houghton Mifflin Company. All rights reserved. 73744_C14L3_RET.indd 19 7/2/07 6:58:13 AM