GCF (HCF) of 40 and 390

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What is the Greatest Common Divisor of 40 and 390?

Answer

GCF (HCF) of 40 and 390 is
10

Common factors: 1, 2, 5, 10

10 divides both: 40 ÷ 10 = 4, 390 ÷ 10 = 39 — and 4 and 39 share no factor but 1, so no larger number divides both.

40 = 23 × 5

390 = 2 × 3 × 5 × 13

Prime40390Lowest power
22322
3—3—
5555
13—13—

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

GCF = 2 × 5 = 10

See Also

FAQ

What is the Greatest Common Divisor of 40 and 390?

GCF (HCF) of 40 and 390 is 10

How to find the GCF of 40 and 390?

You can find the GCF of 40 and 390 by listing all factors of both numbers and picking the greatest common one, or by prime factorization. The GCF of 40 and 390 is 10.

What prime factors do 40 and 390 share?

The prime factorizations of 40 and 390 have 2 × 5 in common, and multiplying those shared primes gives 10 — exactly the greatest common factor.

How does the GCF reduce the fraction 40/390?

Divide the numerator and the denominator by the GCF 10: 40 ÷ 10 = 4 and 390 ÷ 10 = 39. So 40/390 in lowest terms is 4/39.