Solution: The GCF of 99 and 88 is 11
Methods
How to find the GCF of 99 and 88 using Prime Factorization
One way to find the GCF of 99 and 88 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 99?
What are the Factors of 88?
Here is the prime factorization of 99:
3
2
×
1
1
1
3^2 × 11^1
3 2 × 1 1 1
And this is the prime factorization of 88:
2
3
×
1
1
1
2^3 × 11^1
2 3 × 1 1 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 99 and 88 by multiplying all the matching prime factors to get a GCF of 99 and 88 as 121:
Thus, the GCF of 99 and 88 is: 121
How to Find the GCF of 99 and 88 by Listing All Common Factors
The first step to this method of finding the Greatest Common Factor of 99 and 88 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, 99 and 88:
Factors of 99: 1, 3, 9, 11, 33, 99
Factors of 88: 1, 2, 4, 8, 11, 22, 44, 88
When you compare the two lists of factors, you can see that the common factor(s) are 1, 11. Since 11 is the largest of these common factors, the GCF of 99 and 88 would be 11.
Find the GCF of Other Number Pairs
Want more practice? Try some of these other GCF problems:
What is the GCF of 144 and 30?
What is the GCF of 57 and 38?
What is the GCF of 4 and 24?
What is the GCF of 92 and 35?
What is the GCF of 56 and 79?