Solution: The GCF of 90 and 71 is 1
Methods
How to find the GCF of 90 and 71 using Prime Factorization
One way to find the GCF of 90 and 71 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 90?
What are the Factors of 71?
Here is the prime factorization of 90:
2
1
×
3
2
×
5
1
2^1 × 3^2 × 5^1
2 1 × 3 2 × 5 1
And this is the prime factorization of 71:
7
1
1
71^1
7 1 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 90 and 71 is 1.
Thus, the GCF of 90 and 71 is: 1
How to Find the GCF of 90 and 71 by Listing All Common Factors
The first step to this method of finding the Greatest Common Factor of 90 and 71 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, 90 and 71:
Factors of 90: 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90
Factors of 71: 1, 71
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 90 and 71 is 1.
Find the GCF of Other Number Pairs
Want more practice? Try some of these other GCF problems:
What is the GCF of 145 and 118?
What is the GCF of 149 and 132?
What is the GCF of 106 and 56?
What is the GCF of 119 and 21?
What is the GCF of 58 and 17?