Solution: The GCF of 26 and 40 is 2MethodsHow to find the GCF of 26 and 40 using Prime FactorizationOne way to find the GCF of 26 and 40 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 26?What are the Factors of 40?Here is the prime factorization of 26:21×1312^1 × 13^121×131And this is the prime factorization of 40:23×512^3 × 5^123×51When you compare the prime factorization of these two numbers, you can see that there are matching prime factors. You can now find the Greatest Common Factor of 26 and 40 by multiplying all the matching prime factors to get a GCF of 26 and 40 as 4:Thus, the GCF of 26 and 40 is: 4How to Find the GCF of 26 and 40 by Listing All Common FactorsThe first step to this method of finding the Greatest Common Factor of 26 and 40 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, 26 and 40:Factors of 26: 1, 2, 13, 26Factors of 40: 1, 2, 4, 5, 8, 10, 20, 40When you compare the two lists of factors, you can see that the common factor(s) are 1, 2. Since 2 is the largest of these common factors, the GCF of 26 and 40 would be 2.Find the GCF of Other Number PairsWant more practice? Try some of these other GCF problems:What is the GCF of 3 and 78?What is the GCF of 29 and 97?What is the GCF of 8 and 116?What is the GCF of 70 and 22?What is the GCF of 87 and 36?