MAFS.3.MD.3.5 – Recognize area as an attribute of plane figures and understand concepts of area measurement
a. 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.
b. 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.
MAFS.3.MD.3.6 – Measure areas by counting unit squares (square cm, square m, square in, square ft, and improvised units).
MAFS.3.MD.3.7 – Relate area to the operations of multiplication and addition.
b. Multiply side lengths to find areas of rectangles with whole-number side lengths in the context of solving real world and mathematical problems, and represent whole-number products as rectangular areas in mathematical reasoning.
c. Use tiling to show in a concrete case that the area of a rectangle with whole-number side lengths a and b + c is the sum of a × b and a × c. Use area models to represent the distributive property in mathematical reasoning.