GCF for 12, 30 and 42

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

What's the Greatest Common Factor (GCF) of 12, 30 and 42?

Answer

GCF of 12, 30 and 42 is
6

Common factors: 1, 2, 3, 6

6 divides all three: 12 ÷ 6 = 2, 30 ÷ 6 = 5, 42 ÷ 6 = 7 — and 2, 5 and 7 have no factor but 1 common to all of them, so no larger number divides all three.

12 = 22 × 3

30 = 2 × 3 × 5

42 = 2 × 3 × 7

Prime123042Lowest power
222222
33333
5—5——
7——7—

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

GCF = 2 × 3 = 6

More with these numbers

Related Calculations

See Also

GCF Table

1st2nd3rdGCF
1227303
1228302
1229301
1230306
1230311
1230322
1230333
1230342
1230351
1230366
1230371
1230382
1230393
1230402
1230411
1230426
1230431
1230442
1230453
1230462
1230471
1230486
1230491
1230502
1230513
1230522
1230531
1230546
1230551
1230562

FAQ

What's the Greatest Common Factor (GCF) of 12, 30 and 42?

GCF of 12, 30 and 42 is 6

What prime factors do 12, 30 and 42 share?

All three factorizations contain 2 × 3, and multiplying those shared primes gives 6 — exactly the greatest common factor.

Can you get the GCF of 12, 30 and 42 two numbers at a time?

Yes. The GCF of 12 and 30 is 6, and the GCF of 6 and 42 is 6 — 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 12 : 30 : 42?

Divide every term by the GCF 6: 12 ÷ 6 = 2, 30 ÷ 6 = 5 and 42 ÷ 6 = 7. So 12 : 30 : 42 in lowest terms is 2 : 5 : 7, and no whole number other than 1 divides all three of those.

See Also