GCF (HCF) of 42 and 51

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What is the Greatest Common Divisor of 42 and 51?

Answer

GCF (HCF) of 42 and 51 is
3

Common factors: 1, 3

3 divides both: 42 ÷ 3 = 14, 51 ÷ 3 = 17 — and 14 and 17 share no factor but 1, so no larger number divides both.

42 = 2 × 3 × 7

51 = 3 × 17

Prime4251Lowest power
22——
3333
77——
17—17—

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

GCF = 3

See Also

FAQ

What is the Greatest Common Divisor of 42 and 51?

GCF (HCF) of 42 and 51 is 3

How to find the GCF of 42 and 51?

You can find the GCF of 42 and 51 by listing all factors of both numbers and picking the greatest common one, or by prime factorization. The GCF of 42 and 51 is 3.

What prime factors do 42 and 51 share?

The prime factorizations of 42 and 51 have 3 in common, and multiplying those shared primes gives 3 — exactly the greatest common factor.

How does the GCF reduce the fraction 42/51?

Divide the numerator and the denominator by the GCF 3: 42 ÷ 3 = 14 and 51 ÷ 3 = 17. So 42/51 in lowest terms is 14/17.