Finding the Common Factors

Which sentence is true?

• 3 is a common factor of 18 and 24

• 5 is a common factor of 16 and 20

• 7 is a common factor of 28 and 32

• 9 is a common factor of 21 and 36

1, 7 and 35 are factors of 35. What factor is missing?

• 2

• 3

• 5

• 7

What number has 9 as a factor?

• 49

• 56

• 64

• 81

The factors of a number are

(1, 3, 7, 9, 21, 63)

What is the number?

• 72

• 63

• 21

• 18

Which list has all the factors of 18?

• 1, 2, 3, 7, 9, 18

• 1, 2, 3, 4, 9, 18

• 1, 2, 4, 6, 9, 18

• 1, 2, 3, 6, 9, 18

Which list has all the factors of 24?

• 1, 2, 4, 6, 8, 10, 12, 24

• 1, 2, 3, 4, 6, 8, 12, 24

• 1, 2, 3, 4, 5, 8, 12, 24

• 1, 2, 3, 4, 6, 8, 10, 24

The common factors of 18 and 24 are

• 2, 3, 4, 6

• 1, 2, 3, 4

• 1, 2, 3, 6

• 3, 4, 5, 6

The greatest common factor of 18 and 24 is

• 2

• 3

• 6

• 8

Which pair of numbers has a GCF (greatest common factor) of 7?

• 28 and 35

• 14 and 26

• 25 and 30

• 24 and 42

The fourth-grade class is competing in the school field day. There are 32 girls and 40 boys who want to participate. Each team must have the same number of girls and the same number of boys. What is the greatest number of teams that can be formed?

• The greatest number of teams that can be formed is 10.

• The greatest number of teams that can be formed is 8.

• The greatest number of teams that can be formed is 6.

• The greatest number of teams that can be formed is 4.