Let’s solve each part step by step.
We are to find the Greatest Common Factor (GCF) of two numbers.
To do this, we list all the factors of each number, then find the largest factor they have in common.
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a) 30 and 10
Factors of 30:
1, 2, 3, 5, 6, 10, 15, 30
Factors of 10:
1, 2, 5, 10
Common factors: 1, 2, 5, 10
→ GCF =
10
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b) 78 and 26
Factors of 78:
1, 2, 3, 6, 13, 26, 39, 78
Factors of 26:
1, 2, 13, 26
Common factors: 1, 2, 13, 26
→ GCF =
26
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c) 60 and 68
Factors of 60:
1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60
Factors of 68:
1, 2, 4, 17, 34, 68
Common factors: 1, 2, 4
→ GCF =
4
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d) 70 and 20
Factors of 70:
1, 2, 5, 7, 10, 14, 35, 70
Factors of 20:
1, 2, 4, 5, 10, 20
Common factors: 1, 2, 5, 10
→ GCF =
10
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e) 40 and 24
Factors of 40:
1, 2, 4, 5, 8, 10, 20, 40
Factors of 24:
1, 2, 3, 4, 6, 8, 12, 24
Common factors: 1, 2, 4, 8
→ GCF =
8
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Final Answer:
a) 10
b) 26
c) 4
d) 10
e) 8
Parent Tip: Review the logic above to help your child master the concept of greatest common factor worksheet.
