Solution: The GCF of 63 and 145 is 1MethodsHow to find the GCF of 63 and 145 using Prime FactorizationOne way to find the GCF of 63 and 145 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 63?What are the Factors of 145?Here is the prime factorization of 63:32×713^2 × 7^132×71And this is the prime factorization of 145:51×2915^1 × 29^151×291When 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 63 and 145 is 1.Thus, the GCF of 63 and 145 is: 1How to Find the GCF of 63 and 145 by Listing All Common FactorsThe first step to this method of finding the Greatest Common Factor of 63 and 145 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, 63 and 145:Factors of 63: 1, 3, 7, 9, 21, 63Factors of 145: 1, 5, 29, 145When you compare the two lists of factors, you can see that the only common factor is 1. So, in this case, the GCF of 63 and 145 is 1.Find the GCF of Other Number PairsWant more practice? Try some of these other GCF problems:What is the GCF of 150 and 4?What is the GCF of 17 and 96?What is the GCF of 12 and 45?What is the GCF of 112 and 18?What is the GCF of 19 and 142?