How many cubic feet is 108 inches by 60 inches by two inches?

1 ft3 = 12 x 12 x 12 = 1728 in3

48 x 48 x 48 = 110592 : expressed as cu ft this is 110592/1728 = 64 cu ft.

Alternative Method : 48 = 4 x 12 : so 483 = 43 x 123 : as 123 is the conversion factor from cubic feet to cubic inches then the answer in cubic feet is 43 = 64.