Finding the Greatest Common Factor

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Finding the Greatest Common Factor

• Grade 5

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Lesson Objectives

• 6.B.1.c Identify the greatest
• common factor
• 3.A.1.a Use technology tools, including software
  and hardware, from a range of teacher-selected
  options to learn a new content or reinforce skills

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Think Backwards

• Find Factors
• Circle Common Factors
• Group Greatest Factor

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Step 1 Find the Factors

• 24 1,2,3,4,6,8,12,24
• 36 1,2,3,4,6,9,12,18,36

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Step 2 Circle Common Factors

• 24 1,2,3,4,6,8,12,24
• 36 1,2,3,4,6,9,12,18,36

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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

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The Greatest Common Factor of 24 and 36 is

• 12

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Now lets try finding the GCF
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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

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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

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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

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The Greatest Common Factor of 12 and 24 is

• 12

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Your turn!

• Find the Greatest Common Factor of 16 and 20.
• RememberFind Factors, Circle Common, Group
  Greatest!

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The Greatest Common Factor of 16 and 20 is

• 4

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Are you ready?

• Let's try some more!