Solution: The GCF of 26 and 55 is 1MethodsHow to find the GCF of 26 and 55 using Prime FactorizationOne way to find the GCF of 26 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 26?What are the Factors of 55?Here is the prime factorization of 26:21×1312^1 × 13^121×131And this is the prime factorization of 55:51×1115^1 × 11^151×111When 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 26 and 55 is 1.Thus, the GCF of 26 and 55 is: 1How to Find the GCF of 26 and 55 by Listing All Common FactorsThe first step to this method of finding the Greatest Common Factor of 26 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, 26 and 55:Factors of 26: 1, 2, 13, 26Factors of 55: 1, 5, 11, 55When you compare the two lists of factors, you can see that the only common factor is 1. So, in this case, the GCF of 26 and 55 is 1.Find the GCF of Other Number PairsWant more practice? Try some of these other GCF problems:What is the GCF of 118 and 79?What is the GCF of 99 and 133?What is the GCF of 14 and 94?What is the GCF of 138 and 12?What is the GCF of 121 and 45?