GM3-2: Find areas of rectangles and volumes of cuboids by applying multiplication.

Elaboration on this Achievement Objective

This means students will begin by measuring the areas of rectangles and other shapes using square units. This is because square units of the same size tessellate, that is join together with no laps or overlaps. That means that the measurement is consistent whereas the use of a non-tessellating unit would give variable results due to gaps and overlaps. Similarly, volume is measured in cubes of the same size. At Level Three students should apply whole number multiplication to make the process of counting squares or cubes more efficient.


 area array.

 volume array.

4 x 6 = 24 square units

3 x 4 x 6 = 72 cubic units