GCF (HCF) of 20 and 28

"Greatest Common Factor" Calculator
Greatest Common Factor of
and

What is the Greatest Common Divisor of 20 and 28?

Answer

GCF (HCF) of 20 and 28 is
4

Common factors: 1, 2, 4

4 divides both: 20 ÷ 4 = 5, 28 ÷ 4 = 7 — and 5 and 7 share no factor but 1, so no larger number divides both.

20 = 22 × 5

28 = 22 × 7

Prime2028Lowest power
2222222
55——
7—7—

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

GCF = 22 = 4

More with these numbers

Related Calculations

See Also

GCF Table

Number 1Number 2GCF
20124
20155
20211
20222
20231
20244
20255
20262
20271
20284
203010
20324
20355
20364
20382
20391
204020
20422
20444
20455
20471
20484
205010
20555
20564
20582
20591
206020
207010
20755

FAQ

What is the Greatest Common Divisor of 20 and 28?

GCF (HCF) of 20 and 28 is 4

How to find the GCF of 20 and 28?

You can find the GCF of 20 and 28 by listing all factors of both numbers and picking the greatest common one, or by prime factorization. The GCF of 20 and 28 is 4.

What prime factors do 20 and 28 share?

The prime factorizations of 20 and 28 have 2 × 2 in common, and multiplying those shared primes gives 4 — exactly the greatest common factor.

How does the GCF reduce the fraction 20/28?

Divide the numerator and the denominator by the GCF 4: 20 ÷ 4 = 5 and 28 ÷ 4 = 7. So 20/28 in lowest terms is 5/7.

See Also