GCF for 20, 30 and 40

"Greatest Common Factor of 3 Numbers" Calculator
Greatest Common Factor of
,
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What's the Greatest Common Factor (GCF) of 20, 30 and 40?

Answer

GCF of 20, 30 and 40 is
10

Common factors: 1, 2, 5, 10

10 divides all three: 20 ÷ 10 = 2, 30 ÷ 10 = 3, 40 ÷ 10 = 4 — and 2, 3 and 4 have no factor but 1 common to all of them, so no larger number divides all three.

20 = 22 × 5

30 = 2 × 3 × 5

40 = 23 × 5

Prime203040Lowest power
2222232
3—3——
55555

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

GCF = 2 × 5 = 10

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GCF Table

1st2nd3rdGCF
2025305
2026302
2027301
2028302
2029301
20303010
2030311
2030322
2030331
2030342
2030355
2030362
2030371
2030382
2030391
20304010
2030411
2030422
2030431
2030442
2030455
2030462
2030471
2030482
2030491
20305010
2030511
2030522
2030531
2030542

FAQ

What's the Greatest Common Factor (GCF) of 20, 30 and 40?

GCF of 20, 30 and 40 is 10

What prime factors do 20, 30 and 40 share?

All three factorizations contain 2 × 5, and multiplying those shared primes gives 10 — exactly the greatest common factor.

Can you get the GCF of 20, 30 and 40 two numbers at a time?

Yes. The GCF of 20 and 30 is 10, and the GCF of 10 and 40 is 10 — 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 20 : 30 : 40?

Divide every term by the GCF 10: 20 ÷ 10 = 2, 30 ÷ 10 = 3 and 40 ÷ 10 = 4. So 20 : 30 : 40 in lowest terms is 2 : 3 : 4, and no whole number other than 1 divides all three of those.

See Also