Let’s solve each problem step by step. We’ll find the factors of each number, put them in the Venn diagram (common factors go in the middle), and then pick the greatest one for the GCF.
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Problem 1: GCF of 12 and 6
Factors of 12: 1, 2, 3, 4, 6, 12
Factors of 6: 1, 2, 3, 6
Common factors (middle): 1, 2, 3, 6
Greatest common factor =
6
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Problem 2: GCF of 12 and 16
Factors of 12: 1, 2, 3, 4, 6, 12
Factors of 16: 1, 2, 4, 8, 16
Common factors (middle): 1, 2, 4
Greatest common factor =
4
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Problem 3: GCF of 10 and 5
Factors of 10: 1, 2, 5, 10
Factors of 5: 1, 5
Common factors (middle): 1, 5
Greatest common factor =
5
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Problem 4: GCF of 15 and 20
Factors of 15: 1, 3, 5, 15
Factors of 20: 1, 2, 4, 5, 10, 20
Common factors (middle): 1, 5
Greatest common factor =
5
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Problem 5: GCF of 9 and 18
Factors of 9: 1, 3, 9
Factors of 18: 1, 2, 3, 6, 9, 18
Common factors (middle): 1, 3, 9
Greatest common factor =
9
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Problem 6: GCF of 18 and 24
Factors of 18: 1, 2, 3, 6, 9, 18
Factors of 24: 1, 2, 3, 4, 6, 8, 12, 24
Common factors (middle): 1, 2, 3, 6
Greatest common factor =
6
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Final Answer:
GCF of 12 and 6 = 6
GCF of 12 and 16 = 4
GCF of 10 and 5 = 5
GCF of 15 and 20 = 5
GCF of 9 and 18 = 9
GCF of 18 and 24 = 6
Parent Tip: Review the logic above to help your child master the concept of gcf and lcm worksheet pdf.
