5.MD.C.3  Recognize volume as an attribute of solid figures and understand concepts of volume measurement.

5.MD.C.3.a  A cube with side length 1 unit, called a “unit cube,” is said to have “one cubic unit” of volume, and can be used to measure volume.

5.MD.C.3.b  A solid figure which can be packed without gaps or overlaps using n unit cubes is said to have a volume of n cubic units.