Q:

What is the GCF of 70 and 80?

Accepted Solution

A:
Solution: The GCF of 70 and 80 is 10 Methods How to find the GCF of 70 and 80 using Prime Factorization One way to find the GCF of 70 and 80 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 70? What are the Factors of 80? Here is the prime factorization of 70: 2 1 × 5 1 × 7 1 2^1 × 5^1 × 7^1 2 1 × 5 1 × 7 1 And this is the prime factorization of 80: 2 4 × 5 1 2^4 × 5^1 2 4 × 5 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 70 and 80 by multiplying all the matching prime factors to get a GCF of 70 and 80 as 100: Thus, the GCF of 70 and 80 is: 100 How to Find the GCF of 70 and 80 by Listing All Common Factors The first step to this method of finding the Greatest Common Factor of 70 and 80 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, 70 and 80: Factors of 70: 1, 2, 5, 7, 10, 14, 35, 70 Factors of 80: 1, 2, 4, 5, 8, 10, 16, 20, 40, 80 When you compare the two lists of factors, you can see that the common factor(s) are 1, 2, 5, 10. Since 10 is the largest of these common factors, the GCF of 70 and 80 would be 10. Find the GCF of Other Number Pairs Want more practice? Try some of these other GCF problems: What is the GCF of 36 and 57? What is the GCF of 63 and 108? What is the GCF of 71 and 34? What is the GCF of 116 and 144? What is the GCF of 113 and 5?