GCF (HCF) of 42 and 70

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What is the Greatest Common Divisor of 42 and 70?

Answer

GCF (HCF) of 42 and 70 is
14

Common factors: 1, 2, 7, 14

14 divides both: 42 ÷ 14 = 3, 70 ÷ 14 = 5 — and 3 and 5 share no factor but 1, so no larger number divides both.

42 = 2 × 3 × 7

70 = 2 × 5 × 7

Prime4270Lowest power
2222
33——
5—5—
7777

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

GCF = 2 × 7 = 14

See Also

FAQ

What is the Greatest Common Divisor of 42 and 70?

GCF (HCF) of 42 and 70 is 14

How to find the GCF of 42 and 70?

You can find the GCF of 42 and 70 by listing all factors of both numbers and picking the greatest common one, or by prime factorization. The GCF of 42 and 70 is 14.

What prime factors do 42 and 70 share?

The prime factorizations of 42 and 70 have 2 × 7 in common, and multiplying those shared primes gives 14 — exactly the greatest common factor.

How does the GCF reduce the fraction 42/70?

Divide the numerator and the denominator by the GCF 14: 42 ÷ 14 = 3 and 70 ÷ 14 = 5. So 42/70 in lowest terms is 3/5.