Solution: The GCF of 4 and 12 is 4MethodsHow to find the GCF of 4 and 12 using Prime FactorizationOne way to find the GCF of 4 and 12 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 4?What are the Factors of 12?Here is the prime factorization of 4:222^222And this is the prime factorization of 12:22×312^2 × 3^122×31When 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 4 and 12 by multiplying all the matching prime factors to get a GCF of 4 and 12 as 4:Thus, the GCF of 4 and 12 is: 4How to Find the GCF of 4 and 12 by Listing All Common FactorsThe first step to this method of finding the Greatest Common Factor of 4 and 12 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, 4 and 12:Factors of 4: 1, 2, 4Factors of 12: 1, 2, 3, 4, 6, 12When you compare the two lists of factors, you can see that the common factor(s) are 1, 2, 4. Since 4 is the largest of these common factors, the GCF of 4 and 12 would be 4.Find the GCF of Other Number PairsWant more practice? Try some of these other GCF problems:What is the GCF of 147 and 132?What is the GCF of 108 and 44?What is the GCF of 126 and 75?What is the GCF of 27 and 59?What is the GCF of 2 and 140?