Solution: The GCF of 104 and 39 is 13
Methods
How to find the GCF of 104 and 39 using Prime Factorization
One way to find the GCF of 104 and 39 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 104?
What are the Factors of 39?
Here is the prime factorization of 104:
2
3
×
1
3
1
2^3 × 13^1
2 3 × 1 3 1
And this is the prime factorization of 39:
3
1
×
1
3
1
3^1 × 13^1
3 1 × 1 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 104 and 39 by multiplying all the matching prime factors to get a GCF of 104 and 39 as 169:
Thus, the GCF of 104 and 39 is: 169
How to Find the GCF of 104 and 39 by Listing All Common Factors
The first step to this method of finding the Greatest Common Factor of 104 and 39 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, 104 and 39:
Factors of 104: 1, 2, 4, 8, 13, 26, 52, 104
Factors of 39: 1, 3, 13, 39
When you compare the two lists of factors, you can see that the common factor(s) are 1, 13. Since 13 is the largest of these common factors, the GCF of 104 and 39 would be 13.
Find the GCF of Other Number Pairs
Want more practice? Try some of these other GCF problems:
What is the GCF of 128 and 4?
What is the GCF of 5 and 69?
What is the GCF of 122 and 124?
What is the GCF of 40 and 22?
What is the GCF of 140 and 67?