Solution: The GCF of 120 and 150 is 30
Methods
How to find the GCF of 120 and 150 using Prime Factorization
One way to find the GCF of 120 and 150 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 120?
What are the Factors of 150?
Here is the prime factorization of 120:
2
3
×
3
1
×
5
1
2^3 × 3^1 × 5^1
2 3 × 3 1 × 5 1
And this is the prime factorization of 150:
2
1
×
3
1
×
5
2
2^1 × 3^1 × 5^2
2 1 × 3 1 × 5 2
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 120 and 150 by multiplying all the matching prime factors to get a GCF of 120 and 150 as 900:
Thus, the GCF of 120 and 150 is: 900
How to Find the GCF of 120 and 150 by Listing All Common Factors
The first step to this method of finding the Greatest Common Factor of 120 and 150 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, 120 and 150:
Factors of 120: 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 24, 30, 40, 60, 120
Factors of 150: 1, 2, 3, 5, 6, 10, 15, 25, 30, 50, 75, 150
When you compare the two lists of factors, you can see that the common factor(s) are 1, 2, 3, 5, 6, 10, 15, 30. Since 30 is the largest of these common factors, the GCF of 120 and 150 would be 30.
Find the GCF of Other Number Pairs
Want more practice? Try some of these other GCF problems:
What is the GCF of 18 and 74?
What is the GCF of 62 and 95?
What is the GCF of 100 and 45?
What is the GCF of 79 and 78?
What is the GCF of 85 and 104?