Solution: The GCF of 128 and 2 is 2
Methods
How to find the GCF of 128 and 2 using Prime Factorization
One way to find the GCF of 128 and 2 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 128?
What are the Factors of 2?
Here is the prime factorization of 128:
2
7
2^7
2 7
And this is the prime factorization of 2:
2
1
2^1
2 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 128 and 2 by multiplying all the matching prime factors to get a GCF of 128 and 2 as 4:
Thus, the GCF of 128 and 2 is: 4
How to Find the GCF of 128 and 2 by Listing All Common Factors
The first step to this method of finding the Greatest Common Factor of 128 and 2 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, 128 and 2:
Factors of 128: 1, 2, 4, 8, 16, 32, 64, 128
Factors of 2: 1, 2
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 128 and 2 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 96 and 17?
What is the GCF of 4 and 66?
What is the GCF of 90 and 22?
What is the GCF of 48 and 82?
What is the GCF of 127 and 58?