Solution: The GCF of 64 and 15 is 1MethodsHow to find the GCF of 64 and 15 using Prime FactorizationOne way to find the GCF of 64 and 15 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 64?What are the Factors of 15?Here is the prime factorization of 64:262^626And this is the prime factorization of 15:31×513^1 × 5^131×51When 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 64 and 15 is 1.Thus, the GCF of 64 and 15 is: 1How to Find the GCF of 64 and 15 by Listing All Common FactorsThe first step to this method of finding the Greatest Common Factor of 64 and 15 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, 64 and 15:Factors of 64: 1, 2, 4, 8, 16, 32, 64Factors of 15: 1, 3, 5, 15When you compare the two lists of factors, you can see that the only common factor is 1. So, in this case, the GCF of 64 and 15 is 1.Find the GCF of Other Number PairsWant more practice? Try some of these other GCF problems:What is the GCF of 94 and 86?What is the GCF of 33 and 109?What is the GCF of 16 and 58?What is the GCF of 147 and 48?What is the GCF of 63 and 47?