Introduction

Use addition and multiplication to solve problems about the perimeter of irregular and regular 2D shapes, and to find the area of rectilinear and composite rectilinear shapes; use division to solve associated inverse problems.

Teaching points

• Teaching point 1: Perimeter is the distance around the edge of a two-dimensional (2D) shape.
   
• Teaching point 2: Perimeter is measured in units of length and can be calculated by adding together the lengths of the sides of a 2D shape.
   
• Teaching point 3: Multiplication can be used to calculate the perimeter of a regular polygon; when the perimeter is known, side-lengths can be calculated using division.
   
• Teaching point 4: Area is the measurement of the surface of a flat item.
   
• Teaching point 5: Area is measured in square units, such as square centimetres (cm²) and square metres (m²).
   
• Teaching point 6: The area of a rectangle can be calculated using multiplication; the area of a composite rectilinear shape can be found by splitting the shape into smaller rectangles.