GCF for 16, 24 and 40

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

What's the Greatest Common Factor (GCF) of 16, 24 and 40?

Answer

GCF of 16, 24 and 40 is
8

(Eight)

8 is the largest positive integer that divides 16, 24 and 40 without a remainder — every other common divisor of the three divides it too.

Finding the GCF of 16, 24 and 40 by Prime Factorization

Split all three numbers into prime factors, then keep every prime that appears in all three of them, each taken as many times as it appears in the poorest factorization. Multiplying what is left gives the greatest common factor:

All Prime Factors of 16: 2 × 2 × 2 × 2 (exponent form: 24)

All Prime Factors of 24: 2 × 2 × 2 × 3 (exponent form: 23 × 3)

All Prime Factors of 40: 2 × 2 × 2 × 5 (exponent form: 23 × 5)

Prime factor162440Lowest power
224232323
33
55

GCF = 2 × 2 × 2 = 8

Checking the GCF of 16, 24 and 40 Two Numbers at a Time

The greatest common factor is associative, so three numbers can be handled as two pairs — and this is what makes the Euclidean algorithm usable here: run it on the first pair, then run it again on that result and the third number.

GCF(a, b, c) = GCF(GCF(a, b), c)

GCF(16, 24) = 8

GCF(8, 40) = 8

GCF(16, 24, 40) = 8

The answer checks out by division — all three quotients come out whole:

16 ÷ 8 = 2

24 ÷ 8 = 3

40 ÷ 8 = 5

2, 3 and 5 have no common factor left — that is what makes 8 the greatest one.

See Also

About "Greatest Common Factor of 3 Numbers" Calculator

This calculator finds the Greatest Common Factor (GCF) of three numbers at once, without doing it in two passes. For example, it can help you find out what's the Greatest Common Factor (GCF) of 16, 24 and 40? (The answer is: 8). Enter the first number (e.g. '16'), the second (e.g. '24') and the third (e.g. '40'), then hit the 'Calculate' button.
The Greatest Common Factor of three numbers — also called the greatest common divisor (GCD) or highest common factor (HCF) — is the largest positive integer that divides all three of them with zero remainder
"Greatest Common Factor of 3 Numbers" Calculator
Greatest Common Factor of
,
and

GCF Table

Number 1Number 2Number 3GCF
1624251
1624262
1624271
1624284
1624291
1624302
1624311
1624328
1624331
1624342
1624351
1624364
1624371
1624382
1624391
1624408
1624411
1624422
1624431
1624444
1624451
1624462
1624471
1624488
1624491
1624502
1624511
1624524
1624531
1624542

FAQ

What's the Greatest Common Factor (GCF) of 16, 24 and 40?

GCF of 16, 24 and 40 is 8

What prime factors do 16, 24 and 40 share?

All three factorizations contain 2 × 2 × 2, and multiplying those shared primes gives 8 — exactly the greatest common factor.

Can you get the GCF of 16, 24 and 40 two numbers at a time?

Yes, and it is the check this page prints. The GCF of 16 and 24 is 8, and the GCF of 8 and 40 is 8 — 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 16 : 24 : 40?

Divide every term by the GCF 8: 16 ÷ 8 = 2, 24 ÷ 8 = 3 and 40 ÷ 8 = 5. So 16 : 24 : 40 in lowest terms is 2 : 3 : 5, and no whole number other than 1 divides all three of those.