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    GCF for 15, 20 and 42

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

    What's the Greatest Common Factor (GCF) of 15, 20 and 42?

    Answer

    GCF of 15, 20 and 42 is
    1

    Common factors: 1

    Only 1 divides all three: no prime is a factor of each of 15, 20 and 42.

    Pairs do share factors — GCF(15, 20) = 5, GCF(15, 42) = 3, GCF(20, 42) = 2 — just none greater than 1 common to all three.

    15 = 3 × 5

    20 = 22 × 5

    42 = 2 × 3 × 7

    Prime152042Lowest power
    2—222—
    33—3—
    555——
    7——7—

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

    GCF = 1

    More with these numbers

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    https://calculat.io/en/number/greatest-common-factor-of-3-numbers/15--20--42Copy
    <a href="https://calculat.io/en/number/greatest-common-factor-of-3-numbers/15--20--42">What is the GCF of 15, 20 and 42? - Calculatio</a>Copy
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    What is the GCF of 15, 20 and 42? The GCF of 15, 20 and 42 is 1 — the largest number that divides all three with no remainder. Step-by-step solution for three numbers.
    https://calculat.io/en/number/greatest-common-factor-of-3-numbers/15--20--42/generated.jpgCopy

    GCF Table

    1st2nd3rdGCF
    1520271
    1520281
    1520291
    1520305
    1520311
    1520321
    1520331
    1520341
    1520355
    1520361
    1520371
    1520381
    1520391
    1520405
    1520411
    1520421
    1520431
    1520441
    1520455
    1520461
    1520471
    1520481
    1520491
    1520505
    1520511
    1520521
    1520531
    1520541
    1520555
    1520561

    FAQ

    What's the Greatest Common Factor (GCF) of 15, 20 and 42?

    GCF of 15, 20 and 42 is 1

    What prime factors do 15, 20 and 42 share?

    None at all: 15, 20 and 42 have no prime factor in common, so the only positive integer dividing all three is 1 and their GCF is 1.

    Can you get the GCF of 15, 20 and 42 two numbers at a time?

    Yes. The GCF of 15 and 20 is 5, and the GCF of 5 and 42 is 1 — 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 15 : 20 : 42?

    Divide every term by the GCF 1: 15 ÷ 1 = 15, 20 ÷ 1 = 20 and 42 ÷ 1 = 42. So 15 : 20 : 42 in lowest terms is 15 : 20 : 42, and no whole number other than 1 divides all three of those.

    See Also