GCF (HCF) of 15 and 5

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What is the Greatest Common Divisor of 15 and 5?

Answer

GCF (HCF) of 15 and 5 is
5

Common factors: 1, 5

5 divides 15 (15 ÷ 5 = 3), so the GCF is the smaller number itself.

15 = 3 × 5

5 — prime

Prime155Lowest power
33——
5555

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

GCF = 5

See Also

FAQ

What is the Greatest Common Divisor of 15 and 5?

GCF (HCF) of 15 and 5 is 5

How to find the GCF of 15 and 5?

You can find the GCF of 15 and 5 by listing all factors of both numbers and picking the greatest common one, or by prime factorization. The GCF of 15 and 5 is 5.

What prime factors do 15 and 5 share?

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

How does the GCF reduce the fraction 15/5?

Divide the numerator and the denominator by the GCF 5: 15 ÷ 5 = 3 and 5 ÷ 5 = 1. So 15/5 in lowest terms is 3/1.