Understanding Factors and Multiples

In this video, Mr. J explains how to find the greatest common factor (GCF) of three numbers, using 27, 9, and 18 as examples. He begins by defining factors and the GCF, then lists the factors of each number. Mr. J demonstrates how to identify common factors and determine the greatest one shared by all three numbers. The video concludes with the GCF of 27, 9, and 18 being identified as 9.

What is a factor of a number?

• A number that can be added to get the given number

• A number that can be multiplied to get the given number

• A number that can be subtracted to get the given number

• A number that can be divided to get the given number

What is the first step in finding the factors of 27?

• List all even numbers

• Start with the smallest prime number

• Start with 1 and the number itself

• List all prime numbers

Which of the following is a factor of 27?

• 4

• 9

• 5

• 2

When listing factors of 9, why is 3 only listed once?

• Because 3 is not a factor

• Because 3 times 3 equals 9

• Because 3 is an even number

• Because 3 is a prime number

Which of the following is NOT a factor of 9?

• 1

• 3

• 9

• 6

What is the first pair of factors for 18?

• 1 and 18

• 2 and 9

• 3 and 6

• 4 and 5

Which of the following is a factor pair of 18?

• 7 and 2

• 4 and 5

• 3 and 6

• 2 and 8

Which number is a common factor of 27, 9, and 18?

• 2

• 5

• 9

• 4

What is the greatest common factor of 27, 9, and 18?

• 12

• 3

• 6

• 9

Which of the following is NOT a common factor of 27, 9, and 18?

• 9

• 3

• 6

• 1