1. Prime Factorization Coach Lesson 2 Also see textbook pages 14 – 17. Jeff Rhodus 6th Grade Elsanor Elementary Coach Lesson 2 Also see textbook pages 14 – 17. Jeff Rhodus 6th Grade Elsanor Elementary

2. Getting the Idea! A number can be written as the product of all its prime factors. This is called the prime factorization of the number. You can draw a factor tree to help you find the prime factorization of a number. The circled numbers are prime numbers. The prime factorization of 42 is written as 2 x 3 x 7. 42 6 7 2 3

3. Example 1: Question: What is the prime factorization of 18? Strategy: Draw a factor tree. following the steps below. Remember which numbers are prime. Step 1: Draw a factor tree as shown below. The branches may show any two factors of 18 except 1 and 18. 18 2 9 Step 2: Continue the tree until all branches end in prime numbers. 18 2 9 3 3

4. Step 3: Write a product, using all the prime numbers at the ends of the branches. 18 2 9 3 3 Solution: The prime factorization of 18 is 2 x 3 x 3.

5. Example 2: Question: What is the prime factorization of 60? Strategy: Draw a factor tree. Remember which numbers are prime. Step 1: Draw a factor tree as shown below. The branches may show any two factors of 60 except 1 and 60. 60 2 30

6. Step 2: Continue the tree until all branches end in prime numbers. 60 2 30 2 15 3 5 Step 3: Write a product, using all the prime numbers at the ends of the branches. Solution: The prime factorization of 60 is 2 x 2 x 3 x 5.

7. Coached Example: Question: What is the prime factorization of 44? Thinking It Through: Make a tree diagram below. Solution: The prime factorization of 44 is ______________________. 44