Question

What is the greatest common factor of 18 and 20

Answer 1

A greatest common factor is the greather number that divide exactly two numbers.

You have the numbers 18 and 20

To find the greatest common factor you find the dividers of each number (the numbers that can divide 18 and 20 exactly):

`18\colon\lbrace1,2,3,6,9,18\rbrace`
`20\colon\lbrace1,2,4,5,10,20\rbrace`

The common factors are: {1,2}

Then, the greatest common factor of 18 and 20 is 2