Solution: The GCF of 47 and 90 is 1
Methods
How to find the GCF of 47 and 90 using Prime Factorization
One way to find the GCF of 47 and 90 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 47?
What are the Factors of 90?
Here is the prime factorization of 47:
4
7
1
47^1
4 7 1
And this is the prime factorization of 90:
2
1
×
3
2
×
5
1
2^1 × 3^2 × 5^1
2 1 × 3 2 × 5 1
When you compare the prime factorization of these two numbers, you can see that there are no matching prime factors. When this is the case, it means that there are no common factors between these two numbers. As a result, the GCF of 47 and 90 is 1.
Thus, the GCF of 47 and 90 is: 1
How to Find the GCF of 47 and 90 by Listing All Common Factors
The first step to this method of finding the Greatest Common Factor of 47 and 90 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, 47 and 90:
Factors of 47: 1, 47
Factors of 90: 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90
When you compare the two lists of factors, you can see that the only common factor is 1. So, in this case, the GCF of 47 and 90 is 1.
Find the GCF of Other Number Pairs
Want more practice? Try some of these other GCF problems:
What is the GCF of 99 and 146?
What is the GCF of 83 and 82?
What is the GCF of 1 and 91?
What is the GCF of 58 and 68?
What is the GCF of 113 and 106?