Solution: The GCF of 61 and 122 is 61
Methods
How to find the GCF of 61 and 122 using Prime Factorization
One way to find the GCF of 61 and 122 is to compare the prime factorization of each number. To find the prime factorization, you can follow the instructions for each number here:
What are the Factors of 61?
What are the Factors of 122?
Here is the prime factorization of 61:
6
1
1
61^1
6 1 1
And this is the prime factorization of 122:
2
1
×
6
1
1
2^1 × 61^1
2 1 × 6 1 1
When you compare the prime factorization of these two numbers, you can see that there are matching prime factors. You can now find the Greatest Common Factor of 61 and 122 by multiplying all the matching prime factors to get a GCF of 61 and 122 as 3721:
Thus, the GCF of 61 and 122 is: 3721
How to Find the GCF of 61 and 122 by Listing All Common Factors
The first step to this method of finding the Greatest Common Factor of 61 and 122 is to find and list all the factors of each number. Again, you can see how this is done by looking at the “Factors of” articles that are linked to above.
Let’s take a look at the factors for each of these numbers, 61 and 122:
Factors of 61: 1, 61
Factors of 122: 1, 2, 61, 122
When you compare the two lists of factors, you can see that the common factor(s) are 1, 61. Since 61 is the largest of these common factors, the GCF of 61 and 122 would be 61.
Find the GCF of Other Number Pairs
Want more practice? Try some of these other GCF problems:
What is the GCF of 115 and 19?
What is the GCF of 50 and 71?
What is the GCF of 92 and 52?
What is the GCF of 95 and 49?
What is the GCF of 150 and 48?