GCF for 18, 27 and 30

"Greatest Common Factor of 3 Numbers" Calculator
Greatest Common Factor of
,
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What's the Greatest Common Factor (GCF) of 18, 27 and 30?

Answer

GCF of 18, 27 and 30 is
3

Common factors: 1, 3

3 divides all three: 18 ÷ 3 = 6, 27 ÷ 3 = 9, 30 ÷ 3 = 10 — and 6, 9 and 10 have no factor but 1 common to all of them, so no larger number divides all three.

18 = 2 × 32

27 = 33

30 = 2 × 3 × 5

Prime182730Lowest power
22—2—
3323333
5——5—

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

GCF = 3

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GCF Table

1st2nd3rdGCF
1518273
1618271
1718271
1818279
1819271
1820271
1821273
1822271
1823271
1824273
1825271
1826271
1827279
1827281
1827291
1827303
1827311
1827321
1827333
1827341
1827351
1827369
1827371
1827381
1827393
1827401
1827411
1827423
1827431
1827441

FAQ

What's the Greatest Common Factor (GCF) of 18, 27 and 30?

GCF of 18, 27 and 30 is 3

What prime factors do 18, 27 and 30 share?

All three factorizations contain 3, and multiplying those shared primes gives 3 — exactly the greatest common factor.

Can you get the GCF of 18, 27 and 30 two numbers at a time?

Yes. The GCF of 18 and 27 is 9, and the GCF of 9 and 30 is 3 — 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 18 : 27 : 30?

Divide every term by the GCF 3: 18 ÷ 3 = 6, 27 ÷ 3 = 9 and 30 ÷ 3 = 10. So 18 : 27 : 30 in lowest terms is 6 : 9 : 10, and no whole number other than 1 divides all three of those.

See Also