GCF (HCF) of 100 and 120

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What is the Greatest Common Divisor of 100 and 120?

Answer

GCF (HCF) of 100 and 120 is
20

Common factors: 1, 2, 4, 5, 10, 20

20 divides both: 100 ÷ 20 = 5, 120 ÷ 20 = 6 — and 5 and 6 share no factor but 1, so no larger number divides both.

100 = 22 × 52

120 = 23 × 3 × 5

Prime100120Lowest power
2222322
3—3—
55255

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

GCF = 22 × 5 = 20

See Also

FAQ

What is the Greatest Common Divisor of 100 and 120?

GCF (HCF) of 100 and 120 is 20

How to find the GCF of 100 and 120?

You can find the GCF of 100 and 120 by listing all factors of both numbers and picking the greatest common one, or by prime factorization. The GCF of 100 and 120 is 20.

What prime factors do 100 and 120 share?

The prime factorizations of 100 and 120 have 2 × 2 × 5 in common, and multiplying those shared primes gives 20 — exactly the greatest common factor.

How does the GCF reduce the fraction 100/120?

Divide the numerator and the denominator by the GCF 20: 100 ÷ 20 = 5 and 120 ÷ 20 = 6. So 100/120 in lowest terms is 5/6.