Solution: The GCF of 18 and 46 is 2
Methods
How to find the GCF of 18 and 46 using Prime Factorization
One way to find the GCF of 18 and 46 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 18?
What are the Factors of 46?
Here is the prime factorization of 18:
2
1
×
3
2
2^1 × 3^2
2 1 × 3 2
And this is the prime factorization of 46:
2
1
×
2
3
1
2^1 × 23^1
2 1 × 2 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 18 and 46 by multiplying all the matching prime factors to get a GCF of 18 and 46 as 4:
Thus, the GCF of 18 and 46 is: 4
How to Find the GCF of 18 and 46 by Listing All Common Factors
The first step to this method of finding the Greatest Common Factor of 18 and 46 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, 18 and 46:
Factors of 18: 1, 2, 3, 6, 9, 18
Factors of 46: 1, 2, 23, 46
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 18 and 46 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 79 and 89?
What is the GCF of 36 and 136?
What is the GCF of 123 and 62?
What is the GCF of 87 and 45?
What is the GCF of 146 and 116?