GCF for 21 and 56

"Greatest Common Factor" Calculator

Greatest Common Factor of

and

What is the Greatest Common Divisor of 21 and 56?

Answer

GCF of 21 and 56 is 7

(Seven)

Finding GCF for 21 and 56 using all factors (divisors) listing

The first method to find GCF for numbers 21 and 56 is to list all factors for both numbers and pick the highest common one:

All factors of 21: 1, 3, 7, 21

All factors of 56: 1, 2, 4, 7, 8, 14, 28, 56

So the Greatest Common Factor for 21 and 56 is 7

Finding GCF for 21 and 56 by Prime Factorization

The second method to find GCF for numbers 21 and 56 is to list all Prime Factors for both numbers and multiply the common ones:

All Prime Factors of 21: 3, 7

All Prime Factors of 56: 2, 2, 2, 7

As we can see there is only one Prime Factor common to both numbers. It is 7

So 7 is the Greatest Common Factor of 21 and 56

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About "Greatest Common Factor" Calculator

This calculator will help you find the greatest common factor (GCF) of two numbers. For example, it can help you find out what is the Greatest Common Divisor of 21 and 56? (The answer is: 7). Select the first number (e.g. '21') and the second number (e.g. '56'). After that hit the 'Calculate' button.
Greatest Common Factor (GCF) also known as the Greatest Common Divisor (GCD) or Highest Common Factor (HCF) - it is the largest positive integer that divides each of the integers with zero remainder.

"Greatest Common Factor" Calculator

Greatest Common Factor of

and

GCF Table

Number 1 Number 2 GCF
6 56 2
7 56 7
8 56 8
9 56 1
10 56 2
11 56 1
12 56 4
13 56 1
14 56 14
15 56 1
16 56 8
17 56 1
18 56 2
19 56 1
20 56 4
21 56 7
22 56 2
23 56 1
24 56 8
25 56 1
26 56 2
27 56 1
28 56 28
29 56 1
30 56 2
31 56 1
32 56 8
33 56 1
34 56 2
35 56 7

FAQ

What is the Greatest Common Divisor of 21 and 56?
GCF of 21 and 56 is 7

How to find the GCF of 21 and 56?
You can find the GCF of 21 and 56 by listing all factors of both numbers and picking the greatest common one, or by prime factorization. The GCF of 21 and 56 is 7.

See Also