GCF (HCF) of 105 and 120

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What is the Greatest Common Divisor of 105 and 120?

Answer

GCF (HCF) of 105 and 120 is
15

Common factors: 1, 3, 5, 15

15 divides both: 105 ÷ 15 = 7, 120 ÷ 15 = 8 — and 7 and 8 share no factor but 1, so no larger number divides both.

105 = 3 × 5 × 7

120 = 23 × 3 × 5

Prime105120Lowest power
2—23—
3333
5555
77——

— = power 0: the prime is not a factor of this number, so it cannot be in the GCF.

GCF = 3 × 5 = 15

See Also

FAQ

What is the Greatest Common Divisor of 105 and 120?

GCF (HCF) of 105 and 120 is 15

How to find the GCF of 105 and 120?

You can find the GCF of 105 and 120 by listing all factors of both numbers and picking the greatest common one, or by prime factorization. The GCF of 105 and 120 is 15.

What prime factors do 105 and 120 share?

The prime factorizations of 105 and 120 have 3 × 5 in common, and multiplying those shared primes gives 15 — exactly the greatest common factor.

How does the GCF reduce the fraction 105/120?

Divide the numerator and the denominator by the GCF 15: 105 ÷ 15 = 7 and 120 ÷ 15 = 8. So 105/120 in lowest terms is 7/8.