What is the greatest common factor of 90 and 54?

The greatest common factor of 54 and 90 is 18.

To get the Greates Common Factor (GCF) of 90 and 54 we need to factor each value first and then we choose all the copies of factors and multiply them:

90: 2 3 3 5

54: 2 3 3 3

GCF: 2 3 3

The Greates Common Factor (GCF) is: 2 x 3 x 3 = 18