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Greatest common factor (GCF) worksheets Grades 4–5

Find the largest number that divides both numbers.

The front of the free greatest common factor (GCF) worksheet
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Free · Worked example · 28 problems · Answer key · US Letter

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How to do it

The largest number that divides both. List factors or use the prime factors.

GCF of 95 and 19=19\text{GCF of }95\ \text{and }19 = 19
95:1,5,19,9595: 1, 5, 19, 95
19:1,1919: 1, 19
Largest factor in both lists: 19\text{Largest factor in both lists: }19

Example problems

  1. GCF of 6 and 82=\text{GCF of }6\ \text{and }82 =
  2. GCF of 66 and 33=\text{GCF of }66\ \text{and }33 =
  3. GCF of 15 and 9=\text{GCF of }15\ \text{and }9 =
  4. GCF of 21 and 75=\text{GCF of }21\ \text{and }75 =

Factors, multiples and prime numbers

  1. Divisibility rules
  2. Factor pairs
  3. Listing factors
  4. Prime and composite numbers
  5. Prime factorization
  6. Greatest common factor (GCF)
  7. Least common multiple (LCM)
  8. GCF and LCM mixed practice