Solution: The GCF of 143 and 137 is 1MethodsHow to find the GCF of 143 and 137 using Prime FactorizationOne way to find the GCF of 143 and 137 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 143?What are the Factors of 137?Here is the prime factorization of 143:111×13111^1 × 13^1111×131And this is the prime factorization of 137:1371137^11371When 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 143 and 137 is 1.Thus, the GCF of 143 and 137 is: 1How to Find the GCF of 143 and 137 by Listing All Common FactorsThe first step to this method of finding the Greatest Common Factor of 143 and 137 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, 143 and 137:Factors of 143: 1, 11, 13, 143Factors of 137: 1, 137When you compare the two lists of factors, you can see that the only common factor is 1. So, in this case, the GCF of 143 and 137 is 1.Find the GCF of Other Number PairsWant more practice? Try some of these other GCF problems:What is the GCF of 67 and 90?What is the GCF of 47 and 122?What is the GCF of 97 and 21?What is the GCF of 124 and 1?What is the GCF of 79 and 116?