Finding the Greatest Common Factor Grade 5

Lesson Objectives The student will be able to: Find the Greatest Common Factor (GCF) for The given Numbers

Think Backwards… Find Factors Circle Common Factors Group Greatest Factor

Step 1: Find the Factors For 24 & 36 24 ( 1,2,3,4,6,8,12,24) 36 ( 1,2,3,4,6,9,12,18,36)

Step 2: Circle Common Factors 24 ( 1,2,3,4,6,8,12,24) 36 ( 1, 2,3,4,6,9,12,18,36)

Step 3: Group the Greatest Factor 24 – 1,2,3,4,6,8,12,24 36 – 1,2,3,4,6,9,12,18,36

The Greatest Common Factor of 24 and 36 is… 12

Now let’s try finding the GCF

Find the GCF of 12 and 24 Step 1: Find the factors| 12 – 1,2,3,4,6,12 24 – 1,2,3,4,6,8,12,24

Find the GCF of 12 and 24 Step 2: Circle the common factors 12 – 1,2,3,4,6,12 24 – 1,2,3,4,6,8,12,24

Find the GCF of 12 and 24 Step 3: Group the greatest factor 12 – 1 ,2, 3, 4, 6, 12 24 – 1 , 2, 3, 4, 6, 8 , 12,24

The Greatest Common Factor of 12 and 24 is …

Your turn! Find the Greatest Common Factor of 16 and 20. Remember…Find Factors, Circle Common, Group Greatest!

The Greatest Common Factor of 16 and 20 is… 4

Are you ready? Let's try some more!

Greatest Common Factor Two Numbers Factors Common Factors Greatest Common Factor 9 and 12 9 : 1,3,9 12: 1,2,3,4,6,12 1,3 3

Greatest Common Factor Two Numbers Factors Common Factors Greatest Common Factor 6 and 18 6: 1,2,3,6 18: 1,2,3,6,9,18 1,2,3,6 6

What is the greatest common factor of 45 and 105? 15 25 35 45

What is the greatest common factor of 6 and 15? Question 1 Numbers (Year 5, Easy) What is the greatest common factor of 6 and 15? 2 3 6 15 Use pen and paper to work out the answer

What is the greatest common factor of 24 and 40? 4 6 8 12 Use pen and paper to work out the answer