What is the GCF of 56 and 21?
Greatest Common Factor of 56 and 21 is the largest possible number which divides 56 and 21 exactly without any remainder.
Answer: GCF of 56 and 21 is 7
Two methods to find the GCF of 56 and 21 are explained below.
Methods to find GCF of 56 and 21
We can find the GCF by the following methods
 Prime factorization Method
 Long division Method
Method 1 :GCF of 56 and 21 by Prime Factorization
Let us represent 56 and 21 as a product of their prime numbers:
Prime factorization of 56 is 2 x 2 x 2 x 7
Prime factorization of 21 is 3 x 7
Common factors in the prime factorization of 56 and 21 = 7
GCF is the product of the prime factors that are common to prime factorization of 56 and 21
So, the GCF of 56 and 21 is 7
Method 2: GCF of 56 and 21 by Long Division Method

Step 1: Divide 56 by 21 and check the remainder.

Step 2: Make the remainder of the above step as the divisor and the divisor of the above step as the dividend and perform the long division again.

Step 3: Continue till you get the remainder as 0 and GCF of 56 and 21 will be the last divisor.
You can find the GCF of 56 and 21 in any of the above methods but the solution will always remain the same.