3.MD.5 Recognize area as an attribute of plane figures and understand concepts of area measurement.
3.MD.5A A square with side length 1 unit, called ?a unit square,? is said to have ?one square unit? of area, and can be used to measure area.
3.MD.5B A plane figure which can be covered without gaps or overlaps by n unit squares is said to have an area of n square units.