Solution: The GCF of 56 and 86 is 2
Methods
How to find the GCF of 56 and 86 using Prime Factorization
One way to find the GCF of 56 and 86 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 56?
What are the Factors of 86?
Here is the prime factorization of 56:
2
3
×
7
1
2^3 × 7^1
2 3 × 7 1
And this is the prime factorization of 86:
2
1
×
4
3
1
2^1 × 43^1
2 1 × 4 3 1
When 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 56 and 86 by multiplying all the matching prime factors to get a GCF of 56 and 86 as 4:
Thus, the GCF of 56 and 86 is: 4
How to Find the GCF of 56 and 86 by Listing All Common Factors
The first step to this method of finding the Greatest Common Factor of 56 and 86 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, 56 and 86:
Factors of 56: 1, 2, 4, 7, 8, 14, 28, 56
Factors of 86: 1, 2, 43, 86
When 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 56 and 86 would be 2.
Find the GCF of Other Number Pairs
Want more practice? Try some of these other GCF problems:
What is the GCF of 59 and 149?
What is the GCF of 49 and 6?
What is the GCF of 116 and 134?
What is the GCF of 129 and 138?
What is the GCF of 39 and 18?