Solution: The GCF of 32 and 42 is 2MethodsHow to find the GCF of 32 and 42 using Prime FactorizationOne way to find the GCF of 32 and 42 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 32?What are the Factors of 42?Here is the prime factorization of 32:252^525And this is the prime factorization of 42:21×31×712^1 × 3^1 × 7^121×31×71When 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 32 and 42 by multiplying all the matching prime factors to get a GCF of 32 and 42 as 4:Thus, the GCF of 32 and 42 is: 4How to Find the GCF of 32 and 42 by Listing All Common FactorsThe first step to this method of finding the Greatest Common Factor of 32 and 42 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, 32 and 42:Factors of 32: 1, 2, 4, 8, 16, 32Factors of 42: 1, 2, 3, 6, 7, 14, 21, 42When 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 32 and 42 would be 2.Find the GCF of Other Number PairsWant more practice? Try some of these other GCF problems:What is the GCF of 73 and 99?What is the GCF of 52 and 91?What is the GCF of 145 and 43?What is the GCF of 72 and 16?What is the GCF of 58 and 17?