18x18x18
9x2 x 9x2 x 9x2
3x3 x 2 x 3x3 x 2 x 3x3 x 2
(3^6) x (2^3)
24x24x24
12x2 x 12x2 x 12x2
6x2 x 2 x 6x2 x 2 x 6x2 x 2
3x2 x2 x2 x 3x2 x 2 x 2 x 3x2 x 2 x2
(3^3) x (2^9)
at least (3^3) are in each and at least (2^3) are in each
the greatest common factor will be 3^3 x 2^3 = 216
