Question 468092
the greatest common factor of 18, 54, and 90.

try 18 first.

the greatest common factor can't be greater than that.

54/18 = 3, so 18 is a factor of 54.

90/18 = 5, so 18 is also a factor of 90.

18 is definitely a factor of 18, so that's your answer.

the greatest common factor of {18,54,90} is 18.