How do you find the greatest common factor of 55, 75?

1 Answer
Mar 3, 2018

By using the factors of the given numbers, we can find out the GCF.

Explanation:

Write down each of the numbers into its prime factors.
55=5.11
75=3.5.5

Now, circle the common factors of each of the numbers.
You get 5 common from both the numbers. Notice that after circling, you wont find anymore common factors so the GCF is simply 5. ( Each factor can be circled and used only once so 5 cannot be repeated even though 75 has two 5s.)