Find the greatest common factor of two or more numbers Chapter 5 Lesson 2 Objective: Find the greatest common factor of two or more numbers

Vocabulary Greatest Common Factor Factors that are common to two or more numbers.

There are 2 ways to find the GCF! First way is to list the factors Second way is to use Prime Factorization

Lets start by listing the factors

Find the GCF of 20 and 24. 20 1,2,4,5,10,20 24 1,2,3,4,6,8,12,24 GCF is 4

Find the GCF of each pair of numbers. 8 and 10 8: 1,2,4,8 10: 1,2,5,10 GCF is 2 6 and 12 6: 1,2,3,6 12: 1,2,3,4,6,12 GCF is 6

Find the GCF of each pair of numbers. 10 and 17 10: 1,2,5,10 17: 1,17 GCF is 1

Now lets try using prime factorization

Find the GCF if each set of numbers using prime factorization. 18 and 48 18 9 3 3 2 x 3 x 3 48 24 2 12 3 4 2 2 2 x 2 x 2 x 2 x 3 2 x 3 = 6 GCF is 6

Find the GCF of 12 and 78 using prime factorization. You try a few Find the GCF of 12 and 78 using prime factorization. GCF is 6

Find the GCF of 32 and 48 using prime factorization. Try this one Find the GCF of 32 and 48 using prime factorization. GCF is 16

Which way do you like to find the GCF? QUESTION??? Which way do you like to find the GCF? Why?

Try some on your own. Page 205 numbers 9-29 odd Homework Page 205 numbers 10-30 even