Calculate the volume of each shape.
Volume of rectangle = 6 x 5/6 x 1 2/6 = 6 2/3 cubic inches.
Volume of cube = 1/6 x 1/6 x 1/6 = 1/216 cubic inch.
Now divide the volume of the rectangle by the volume of the cube:
6 2/3 / 1/216 = 1440
It will take 1.440 cubes to fill the rectangle.
