4-3 Greatest Common Factor Warm Up Write the prime factorization of each number  73 2  7 2   3 3

4-3 Greatest Common Factor Greatest Common Factor (GCF)- the largest of the common factors shared.. Factors of 24: Factors of 36: Common factors: 1,2,3,4,6, 8, 1, 2, 3, 4, 6, GCF = 12 1,2,3,4,6, 9, 12, 12, 18,

4-3 Greatest Common Factor Ex. 1 Find the GCF of the set of numbers. 28 and 42 Method 1: List the factors. factors of 28: factors of 42: 1,2,14,7,28 7,1, 4, 3,2,426,21,14, List all the factors. Circle the GCF. The GCF of 28 and 42 is 14.

4-3 Greatest Common Factor Ex. 2 Find the GCF of the set of numbers. 18 and 36 Method 1: List the factors. factors of 18: factors of 36: 1,2, 9,6,18 6,1, 3, 2,364,12,9, List all the factors. Circle the GCF. The GCF of 18 and 36 is ,

4-3 Greatest Common Factor Ex. 3 Find the GCF of the set of numbers. 18, 30, and 24 Method 2: Use the prime factorization. 18 = 30 = 24 = Write the prime factorization of each number. Find the common prime factors. The GCF of 18, 30, and 24 is 6. Find the prime factors common to all the numbers. 2 3 =6

4-3 Greatest Common Factor Ex. 4 Find the GCF of the set of numbers. 10, 20, and 30 Method 2: Use the prime factorization. 10 = 20 = 30 = Write the prime factorization of each number. Find the common prime factors. The GCF of 10, 20, and 30 is 10. Find the prime factors common to all the numbers. 2 5 =10

4-3 Greatest Common Factor Ex. 5 Find the GCF of the set of numbers. 45, 18, and 27 Method 3: Use a ladder diagram Begin with a factor that divides into each number. Keep dividing until the three have no common factors. Find the product of the numbers you divided by. 3 3 = The GCF of 45, 18, and 27 is

4-3 Greatest Common Factor Ex. 6 Find the GCF of the set of numbers. 40, 16, and 24 Method 3: Use a ladder diagram Begin with a factor that divides into each number. Keep dividing until the three have no common factors. Find the product of the numbers you divided by =2 2 2 = The GCF of 40, 16, and 24 is

4-3 Greatest Common Factor Ex. 7 Peter has 18 oranges and 27 pears. He wants to make fruit baskets with the same number of each fruit in each basket. What is the greatest number of fruit baskets he can make?

4-3 Greatest Common Factor The answer will be the greatest number of fruit baskets 18 oranges and 27 pears can form so that each basket has the same number of oranges, and each basket has the same number of pears. 1 Understand the Problem 2 Make a Plan You can make an organized list of the possible fruit baskets. Ex. 7 continued

4-3 Greatest Common Factor Solve 3 The greatest number of baskets Peter can make is BouquetsPearsOranges OO PPP 18 oranges, 27 pears: Every fruit is in a basket OO PPP OO PPP OO PPP OO PPP OO PPP OO PPP OO PPP Look Back 4 To form the largest number of baskets, find the GCF of 18 and 27. factors of 18: factors of 27: 1, 3, 2, 186, 1,9,3, 27 The GCF of 18 and 27 is 9. OO PPP 9,

4-3 Greatest Common Factor Standard Lesson Quiz Lesson Quizzes Lesson Quiz for Student Response Systems

4-3 Greatest Common Factor Lesson Quiz: Part I and and , 28, , 66, Find the greatest common factor of each set of numbers.

4-3 Greatest Common Factor Lesson Quiz: Part II 5. Mrs. Lovejoy makes flower arrangements. She has 36 red carnations, 60 white carnations, and 72 pink carnations. Each arrangement must have the same number of each color. What is the greatest number of arrangements she can make if every carnation is used? Find the greatest common factor of the set of numbers. 12 arrangements

4-3 Greatest Common Factor 1. Identify the greatest common factor of 28 and 36. A. 2 B. 4 C. 6 D. 7 Lesson Quiz for Student Response Systems

4-3 Greatest Common Factor 2. Identify the greatest common factor of 49 and 77. A. 3 B. 5 C. 7 D. 11 Lesson Quiz for Student Response Systems

4-3 Greatest Common Factor 3. Identify the greatest common factor of 16, 24, and 40. A. 2 B. 4 C. 5 D. 8 Lesson Quiz for Student Response Systems

4-3 Greatest Common Factor 4. Identify the greatest common factor of 42, 63, and 84. A. 3 B. 7 C. 19 D. 21 Lesson Quiz for Student Response Systems

4-3 Greatest Common Factor 5. Harry collected 42 first-aid kits, 56 blankets, and 70 food packets for a flood-relief camp. He wants to pack the collected items in boxes in such a way that each box has the same number of items of each kind. What is the greatest number of boxes that Harry needs? A. 7 boxes B. 14 boxes C. 21 boxes D. 24 boxes Lesson Quiz for Student Response Systems