Solution: The GCF of 97 and 45 is 1MethodsHow to find the GCF of 97 and 45 using Prime FactorizationOne way to find the GCF of 97 and 45 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 97?What are the Factors of 45?Here is the prime factorization of 97:97197^1971And this is the prime factorization of 45:32×513^2 × 5^132×51When 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 97 and 45 is 1.Thus, the GCF of 97 and 45 is: 1How to Find the GCF of 97 and 45 by Listing All Common FactorsThe first step to this method of finding the Greatest Common Factor of 97 and 45 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, 97 and 45:Factors of 97: 1, 97Factors of 45: 1, 3, 5, 9, 15, 45When you compare the two lists of factors, you can see that the only common factor is 1. So, in this case, the GCF of 97 and 45 is 1.Find the GCF of Other Number PairsWant more practice? Try some of these other GCF problems:What is the GCF of 13 and 136?What is the GCF of 118 and 44?What is the GCF of 78 and 29?What is the GCF of 51 and 117?What is the GCF of 11 and 92?