Session 3: Identify common factors and GCF of two numbers

GCF is the _______ common factor among the given numbers.

• Minimum

• Largest

• Middle

Given the factors of 12 and 16 below: What are its common factors?

12 - 1, 2, 3, 4, 6, 12

16 - 1, 2, 4, 8, 16

• 4

• 2, 4

• 1, 2, 4

• 1, 2, 4, 8

What is the GCF of 20 and 40 if its common factors are 1, 2, 4, 5, 10, 20?

• 1

• 20

• 40

• 60

What is the GCF of 10 and 12?

(You may use any method)

• 2

• 4

• 5

• 8

What is the GCF of 14 and 21?

• 1

• 3

• 5

• 7