What is the greatest common factor for 18 51 and 81?

Answer 1

The greatest common factor is . You can figure this out by finding all of the factors of the smallest number, then, starting with the largest factor, seeing if it is a factor of all the numbers. The factors of 18 are 18, 9, 6, 3, 2, and 1. 18 is not a factor of 51 or 81 (you know quickly because it is an even number while 51 and 81 are odd), 9 isn't (because 5+1 does not = 9 or a multiple of 9), and 6 isn't for the same reason as 18. 3 is a factor of all three (you can tell quickly because 5+1 and 8+1 both add up to multiples of 3), making it the greatest common factor. While 1 is also a factor of all three numbers, it is not the greatest common factor because 3 is larger.

Answer 2

The GCF is 3.

Answer 3

The GCF is 3.

Answer 4

The answer's 9

Answer 5

The GCF of 15 51 and 81 is 3

Answer 6

It is: 3

Answer 7

3