Find the GCF. Use prime factorization.
- 48 and 56 25. 64 and 96 26. 36 and 72 27. 80 and 100
- 45 and 75 29. 39 and 104 30. 48 and 84 31. 100 and 125
- 14, 49, and 70 33.48, 80, and 112 34.18, 54, and 90
Find a pair of numbers:
- Between 10 and 20 that have 6 36. Between 12 and 18 that have 4
as their GCF. as their GCF. - Between 15 and 30 that have 5 38. Between 16 and 24 that have 8
as their GCF. as their GCF.
9
27
3 3 3
3
54
9 6
3 3 3 2
- Can the greatest common factor of 8 and 32 be greater than 8?
Explain your reasoning.
Find the GCF Using Prime Factorization
Find the GCF of 27 and 54.
- First use factor trees to find the prime factors of each number.
Finding the prime factors of a number is called prime factorization. - Then multiply the prime factors that are common to both to find the GCF.
common to both
27 3 3 354 2 3 3 3
3 3 3 27
GCF of 27 and 54: 27
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