GCF for 3, 12 and 18

"Greatest Common Factor of 3 Numbers" Calculator
Greatest Common Factor of
,
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What's the Greatest Common Factor (GCF) of 3, 12 and 18?

Answer

GCF of 3, 12 and 18 is
3

Common factors: 1, 3

3 divides all three: 3 ÷ 3 = 1, 12 ÷ 3 = 4, 18 ÷ 3 = 6 — and 1, 4 and 6 have no factor but 1 common to all of them, so no larger number divides all three.

3 — prime

12 = 22 × 3

18 = 2 × 32

Prime31218Lowest power
2—222—
333323

— = 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
33123
34121
35121
36123
37121
38121
39123
310121
311121
312123
312131
312141
312153
312161
312171
312183
312191
312201
312213
312221
312231
312243
312251
312261
312273
312281
312291
312303
312311
312321

FAQ

What's the Greatest Common Factor (GCF) of 3, 12 and 18?

GCF of 3, 12 and 18 is 3

What prime factors do 3, 12 and 18 share?

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

Can you get the GCF of 3, 12 and 18 two numbers at a time?

Yes. The GCF of 3 and 12 is 3, and the GCF of 3 and 18 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 3 : 12 : 18?

Divide every term by the GCF 3: 3 ÷ 3 = 1, 12 ÷ 3 = 4 and 18 ÷ 3 = 6. So 3 : 12 : 18 in lowest terms is 1 : 4 : 6, and no whole number other than 1 divides all three of those.

See Also