Solution: The GCF of 17 and 55 is 1
Methods
How to find the GCF of 17 and 55 using Prime Factorization
One way to find the GCF of 17 and 55 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 17?
What are the Factors of 55?
Here is the prime factorization of 17:
1
7
1
17^1
1 7 1
And this is the prime factorization of 55:
5
1
×
1
1
1
5^1 × 11^1
5 1 × 1 1 1
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 17 and 55 is 1.
Thus, the GCF of 17 and 55 is: 1
How to Find the GCF of 17 and 55 by Listing All Common Factors
The first step to this method of finding the Greatest Common Factor of 17 and 55 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, 17 and 55:
Factors of 17: 1, 17
Factors of 55: 1, 5, 11, 55
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 17 and 55 is 1.
Find the GCF of Other Number Pairs
Want more practice? Try some of these other GCF problems:
What is the GCF of 107 and 115?
What is the GCF of 127 and 33?
What is the GCF of 108 and 134?
What is the GCF of 22 and 110?
What is the GCF of 94 and 145?