What is the GCF of 21 and 49?
Greatest Common Factor of two numbers is the greatest possible number which divides 21 and 49 exactly without any remainder.
Answer: GCF of 21 and 49 is 7
Two methods to find the GCF of 21 and 49 are explained below.
Methods to find GCF of 72 and 90
 Listing the common factors Method
 Long division Method
Method 1: GCF of 21 and 49 by Listing the Common Factors
Factors of 21: 1, 3, 7, and 21
Factors of 49: 1, 7, and 49
Common Factors of 21 and 49: 1 and 7
Greatest Common Factor of 21 and 49 from the list = 7
GCF of 21 and 49 is 7
Method 2: GCF of 21 and 49 by Long Division Method

Step 1: Divide 49 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
The GCF of 21 and 49 will be the last divisor in the division process.
So, the last divisor is 7
Clearly, in both the methods, the GCF of 21 and 49 is the same.