GCF (HCF) of 20 and 165

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What is the Greatest Common Divisor of 20 and 165?

Answer

GCF (HCF) of 20 and 165 is
5

Common factors: 1, 5

5 divides both: 20 ÷ 5 = 4, 165 ÷ 5 = 33 — and 4 and 33 share no factor but 1, so no larger number divides both.

20 = 22 × 5

165 = 3 × 5 × 11

Prime20165Lowest power
222——
3—3—
5555
11—11—

— = 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 20 and 165?

GCF (HCF) of 20 and 165 is 5

How to find the GCF of 20 and 165?

You can find the GCF of 20 and 165 by listing all factors of both numbers and picking the greatest common one, or by prime factorization. The GCF of 20 and 165 is 5.

What prime factors do 20 and 165 share?

The prime factorizations of 20 and 165 have 5 in common, and multiplying those shared primes gives 5 — exactly the greatest common factor.

How does the GCF reduce the fraction 20/165?

Divide the numerator and the denominator by the GCF 5: 20 ÷ 5 = 4 and 165 ÷ 5 = 33. So 20/165 in lowest terms is 4/33.