Solution: The GCF of 27 and 89 is 1MethodsHow to find the GCF of 27 and 89 using Prime FactorizationOne way to find the GCF of 27 and 89 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 27?What are the Factors of 89?Here is the prime factorization of 27:333^333And this is the prime factorization of 89:89189^1891When 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 27 and 89 is 1.Thus, the GCF of 27 and 89 is: 1How to Find the GCF of 27 and 89 by Listing All Common FactorsThe first step to this method of finding the Greatest Common Factor of 27 and 89 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, 27 and 89:Factors of 27: 1, 3, 9, 27Factors of 89: 1, 89When you compare the two lists of factors, you can see that the only common factor is 1. So, in this case, the GCF of 27 and 89 is 1.Find the GCF of Other Number PairsWant more practice? Try some of these other GCF problems:What is the GCF of 64 and 69?What is the GCF of 145 and 67?What is the GCF of 111 and 97?What is the GCF of 79 and 65?What is the GCF of 129 and 93?