 # Greatest Common Factor

## Presentation on theme: "Greatest Common Factor"— Presentation transcript:

Greatest Common Factor
2-5 Greatest Common Factor Course 2 Warm Up Problem of the Day Lesson Presentation

Greatest Common Factor
Course 2 2-5 Greatest Common Factor Warm Up Write the prime factorization of each number. 1. 20 2. 100 3. 30 4. 128 5. 70 22 · 5 22 · 52 2 · 3 · 5 27 2 · 5 · 7

Greatest Common Factor
Course 2 2-5 Greatest Common Factor Problem of the Day: Part 1 Use the clues to find the numbers being described. 1. a. The greatest common factor (GCF) of two numbers is 5. b. The sum of the numbers is 75. c. The difference between the numbers is 5. 35 and 40

Greatest Common Factor
Course 2 2-5 Greatest Common Factor Problem of the Day: Part 2 Use the clues to find the numbers being described. 2. a. The GCF of three different numbers is 4. b. The sum of the numbers is 64. Possible answer: 12, 16, 36

Greatest Common Factor
Course 2 2-5 Greatest Common Factor Learn to find the greatest common factor of two or more whole numbers.

Insert Lesson Title Here
Course 2 2-5 Greatest Common Factor Insert Lesson Title Here Vocabulary greatest common factor (GCF)

Greatest Common Factor
Course 2 2-5 Greatest Common Factor The greatest common factor (GCF) of two or more whole numbers is the greatest whole number that divides evenly into each number. One way to find the GCF of two or more numbers is to list all the factors of each number. The GCF is the greatest factor that appears in all the lists.

Additional Example 1: Using a List to Find the GCF
Course 2 2-5 Greatest Common Factor Additional Example 1: Using a List to Find the GCF Find the greatest common factor (GCF). 12, 36, 54 List all of the factors of each number. 12: 1, 2, 3, 4, 6, 12 36: 1, 2, 3, 4, 6, 9, 12, 18, 36 Circle the greatest factor that is in all the lists. 54: 1, 2, 3, 6, 9, 18, 27, 54 The GCF is 6.

Insert Lesson Title Here
Course 2 2-5 Greatest Common Factor Insert Lesson Title Here Try This: Example 1 Find the greatest common factor (GCF). 14, 28, 63 List all of the factors of each number. 14: 1, 2, 7, 14 28: 1, 2, 4, 7, 14, 28 Circle the greatest factor that is in all the lists. 63: 1, 3, 7, 9, 21, 63 The GCF is 7.

Additional Example 2A: Using Prime Factorization to Find the GCF
Course 2 2-5 Greatest Common Factor Additional Example 2A: Using Prime Factorization to Find the GCF Find the greatest common factor (GCF). A. 40, 56 Write the prime factorization of each number and circle the common factors. 40 = 2 · 2 · 2 · 5 56 = 2 · 2 · 2 · 7 2 · 2 · 2 = 8 Multiply the common prime factors. The GFC is 8.

Additional Example 2B: Using Prime Factorization to Find the GCF
Course 2 2-5 Greatest Common Factor Additional Example 2B: Using Prime Factorization to Find the GCF Find the greatest common factor (GCF). B. 252, 180, 96, 60 Write the prime factorization of each number and circle the common prime factors. 252 = 2 · 2 · 3 · 3 · 7 180 = 2 · 2 · 3 · 3 · 5 96 = 2 · 2 · 2 · 2 · 2 · 3 60 = 2 · 2 · 3 · 5 2 · 2 · 3 = 12 Multiply the common prime factors. The GCF is 12.

Insert Lesson Title Here
Course 2 2-5 Greatest Common Factor Insert Lesson Title Here Try This: Example 2A Find the greatest common factor (GCF). A. 72, 84 72 = 2 · 2 · 2 · 9 Write the prime factorization of each number and circle the common factors. 84 = 2 · 2 · 7 · 3 2 · 2 = 4 Multiply the common prime factors. The GCF is 4.

Insert Lesson Title Here
Course 2 2-5 Greatest Common Factor Insert Lesson Title Here Try This: Example 2B Find the greatest common factor (GCF). B. 360, 250, 170, 40 360 = 2 · 2 · 2 · 9 · 5 Write the prime factorization of each number and circle the common prime factors. 250 = 2 · 5 · 5 · 5 170 = 2 · 5 · 17 40 = 2 · 2 · 2 · 5 Multiply the common prime factors. 2 · 5 = 10 The GCF is 10.

Additional Example 3: Problem Solving Application
Course 2 2-5 Greatest Common Factor Additional Example 3: Problem Solving Application You have 120 red beads, 100 white beads, and 45 blue beads. You want to use all the beads to make bracelets that have red, white, and blue beads on each. What is the greatest number of matching bracelets you can make?

Understand the Problem
Course 2 2-5 Greatest Common Factor Additional Example 3 Continued 1 Understand the Problem Rewrite the question as a statement. • Find the greatest number of matching bracelets you can make. List the important information: • There are 120 red beads, 100 white beads, and 45 blue beads. • Each bracelet must have the same number of red, white, and blue beads. The answer will be the GCF of 120, 100, and 45.

Course 2 2-5 Greatest Common Factor Additional Example 3 Continued 2 Make a Plan You can list the prime factors of 120, 100, and 45 to find the GFC. Solve 3 120 = 2 · 2 · 2 · 3 · 5 100 = 2 · 2 · 5 · 5 45 = 3 · 3 · 5 The GFC of 120, 100, and 45 is 5. You can make 5 bracelets.

Course 2 2-5 Greatest Common Factor Additional Example 3 Continued Look Back 4 If you make 5 bracelets, each one will have 24 red beads, 20 white beads, and 9 blue beads, with nothing left over.

Insert Lesson Title Here
Course 2 2-5 Greatest Common Factor Insert Lesson Title Here Try This: Example 3 Nathan has made fishing flies that he plans to give away as gift sets. He has 24 wet flies and 18 dry flies. Using all of the flies, how many sets can he make?

Understand the Problem
Course 2 2-5 Greatest Common Factor Insert Lesson Title Here Try This: Example 3 Continued 1 Understand the Problem Rewrite the question as a statement. • Find the greatest number of sets of flies he can make. List the important information: • There are 24 wet flies and 18 dry flies. • He must use all of the flies. The answer will be the GCF of 24 and 18.

Try This: Example 3 Continued
Course 2 2-5 Greatest Common Factor Try This: Example 3 Continued 2 Make a Plan You can list the prime factors of 24 and 18 to find the GCF. Solve 3 24 = 2 · 2 · 2 · 3 18 = 2 · 3 · 3 Multiply the prime factors that are common to both 24 and 18. 2 · 3 = 6 You can make 6 sets of flies.

Greatest Common Factor Insert Lesson Title Here
Course 2 2-5 Greatest Common Factor Insert Lesson Title Here Try This: Example 3 Continued Look Back 4 If you make 6 sets, each set will have 3 dry flies and 4 wet flies.

Greatest Common Factor Insert Lesson Title Here
Course 2 2-5 Greatest Common Factor Insert Lesson Title Here Lesson Quiz: Part 1 Find the greatest common factor (GCF). 1. 28, 40 2. 24, 56 3. 54, 99 4. 20, 35, 70 4 8 9 5

Greatest Common Factor Insert Lesson Title Here
Course 2 2-5 Greatest Common Factor Insert Lesson Title Here Lesson Quiz: Part 2 5. The math clubs from 3 schools agreed to a competition. Members from each club must be divided into teams, and teams from all clubs must be equally sized. What is the greatest number of members that can be on a team if Georgia has 16 members, William has 24 members, and Fulton has 72 members? 8