Solution: The GCF of 49 and 18 is 1
Methods
How to find the GCF of 49 and 18 using Prime Factorization
One way to find the GCF of 49 and 18 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 49?
What are the Factors of 18?
Here is the prime factorization of 49:
7
2
7^2
7 2
And this is the prime factorization of 18:
2
1
×
3
2
2^1 × 3^2
2 1 × 3 2
When you compare the prime factorization of these two numbers, you can see that there are no matching prime factors. When this is the case, it means that there are no common factors between these two numbers. As a result, the GCF of 49 and 18 is 1.
Thus, the GCF of 49 and 18 is: 1
How to Find the GCF of 49 and 18 by Listing All Common Factors
The first step to this method of finding the Greatest Common Factor of 49 and 18 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, 49 and 18:
Factors of 49: 1, 7, 49
Factors of 18: 1, 2, 3, 6, 9, 18
When you compare the two lists of factors, you can see that the only common factor is 1. So, in this case, the GCF of 49 and 18 is 1.
Find the GCF of Other Number Pairs
Want more practice? Try some of these other GCF problems:
What is the GCF of 133 and 122?
What is the GCF of 99 and 42?
What is the GCF of 10 and 126?
What is the GCF of 21 and 40?
What is the GCF of 82 and 53?