GCF for 56, 80 and 140

"Greatest Common Factor of 3 Numbers" Calculator
Greatest Common Factor of
,
and

What's the Greatest Common Factor (GCF) of 56, 80 and 140?

Answer

GCF of 56, 80 and 140 is
4

(Four)

4 is the largest positive integer that divides 56, 80 and 140 without a remainder — every other common divisor of the three divides it too.

Finding the GCF of 56, 80 and 140 by Prime Factorization

Split all three numbers into prime factors, then keep every prime that appears in all three of them, each taken as many times as it appears in the poorest factorization. Multiplying what is left gives the greatest common factor:

All Prime Factors of 56: 2 × 2 × 2 × 7 (exponent form: 23 × 7)

All Prime Factors of 80: 2 × 2 × 2 × 2 × 5 (exponent form: 24 × 5)

All Prime Factors of 140: 2 × 2 × 5 × 7 (exponent form: 22 × 5 × 7)

Prime factor5680140Lowest power
223242222
555
777

GCF = 2 × 2 = 4

Checking the GCF of 56, 80 and 140 Two Numbers at a Time

The greatest common factor is associative, so three numbers can be handled as two pairs — and this is what makes the Euclidean algorithm usable here: run it on the first pair, then run it again on that result and the third number.

GCF(a, b, c) = GCF(GCF(a, b), c)

GCF(56, 80) = 8

GCF(8, 140) = 4

GCF(56, 80, 140) = 4

The answer checks out by division — all three quotients come out whole:

56 ÷ 4 = 14

80 ÷ 4 = 20

140 ÷ 4 = 35

14, 20 and 35 have no common factor left — that is what makes 4 the greatest one.

See Also

About "Greatest Common Factor of 3 Numbers" Calculator

This calculator finds the Greatest Common Factor (GCF) of three numbers at once, without doing it in two passes. For example, it can help you find out what's the Greatest Common Factor (GCF) of 56, 80 and 140? (The answer is: 4). Enter the first number (e.g. '56'), the second (e.g. '80') and the third (e.g. '140'), then hit the 'Calculate' button.
The Greatest Common Factor of three numbers — also called the greatest common divisor (GCD) or highest common factor (HCF) — is the largest positive integer that divides all three of them with zero remainder
"Greatest Common Factor of 3 Numbers" Calculator
Greatest Common Factor of
,
and

GCF Table

Number 1Number 2Number 3GCF
56801251
56801262
56801271
56801288
56801291
56801302
56801311
56801324
56801331
56801342
56801351
56801368
56801371
56801382
56801391
56801404
56801411
56801422
56801431
56801448
56801451
56801462
56801471
56801484
56801491
56801502
56801511
56801528
56801531
56801542

FAQ

What's the Greatest Common Factor (GCF) of 56, 80 and 140?

GCF of 56, 80 and 140 is 4

What prime factors do 56, 80 and 140 share?

All three factorizations contain 2 × 2, and multiplying those shared primes gives 4 — exactly the greatest common factor.

Can you get the GCF of 56, 80 and 140 two numbers at a time?

Yes, and it is the check this page prints. The GCF of 56 and 80 is 8, and the GCF of 8 and 140 is 4 — the same answer, because the greatest common factor is associative and does not depend on the order of the three numbers.

How does the GCF simplify the ratio 56 : 80 : 140?

Divide every term by the GCF 4: 56 ÷ 4 = 14, 80 ÷ 4 = 20 and 140 ÷ 4 = 35. So 56 : 80 : 140 in lowest terms is 14 : 20 : 35, and no whole number other than 1 divides all three of those.