You need
1-inch cubes to fill a cube that has an edge length of 1 foot.

How can this result help you convert a volume from cubic inches to cubic feet? from cubic feet to cubic inches?

The volume of a cube with a side length of 1 foot is cubic _ foot, or _ cubic inches. So, 1 cubic foot is equal to cubic _ inches. The ratios of _ cubic inches to _ cubic foot and cubic foot to cubic inches can be used to convert between cubic inches and cubic feet.