Solution: The GCF of 71 and 80 is 1MethodsHow to find the GCF of 71 and 80 using Prime FactorizationOne way to find the GCF of 71 and 80 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 71?What are the Factors of 80?Here is the prime factorization of 71:71171^1711And this is the prime factorization of 80:24×512^4 × 5^124×51When 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 71 and 80 is 1.Thus, the GCF of 71 and 80 is: 1How to Find the GCF of 71 and 80 by Listing All Common FactorsThe first step to this method of finding the Greatest Common Factor of 71 and 80 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, 71 and 80:Factors of 71: 1, 71Factors of 80: 1, 2, 4, 5, 8, 10, 16, 20, 40, 80When you compare the two lists of factors, you can see that the only common factor is 1. So, in this case, the GCF of 71 and 80 is 1.Find the GCF of Other Number PairsWant more practice? Try some of these other GCF problems:What is the GCF of 107 and 27?What is the GCF of 95 and 125?What is the GCF of 62 and 91?What is the GCF of 99 and 69?What is the GCF of 15 and 118?