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Cotmanhay Junior School

Safe, Happy Learning

Week 9 - 10 Perimeter and area

National curriculum content


  • Pupils use their knowledge of place value and multiplication and division to convert between standard units
  • Pupils calculate the perimeter of rectangles and related composite shapes, including using the relations of perimeter or area to find unknown lengths
  • Missing measures questions such as these can be expressed algebraically, for example 4 + 2b = 20 for a rectangle of sides 2 cm and b cm and perimeter of 20cm
  • Pupils calculate the area from scale drawings using given measurements


Lesson objectives

  1. Perimeter of rectangles
  2. Perimeter of rectilinear shapes
  3. Perimeter of polygons
  4. Area of rectangles
  5. Area of compound shapes
  6. Estimate area


What we want children to know

  • Convert between different units of metric measure (for example, kilometre and metre; centimetre and metre; centimetre and millimetre)
  • Measure and calculate the perimeter of composite rectilinear shapes in centimetres and metres
  • Calculate and compare the area of rectangles (including squares), and including using standard units, square centimetres (cm2 ) and square metres (m2 ) and estimate the area of irregular shapes


What skills we want children to develop

Use knowledge to solve Reasoning and Problem Solving questions such as:


Possible answers

Two shapes are made up of squares of the same size

Jack says these 2 shapes have the same area.

Rosie says the 1st shape is bigger as it takes up more space.

Who is correct?


Vocabulary/Mathematical Talk

  • Which measurement would be more effective to use to measure book/playground?
  • How could I calculate a missing side of a rectangle/square?
  • Show your method of working out the area of a compound shape
  • What do you need to know to estimate the area of an irregular shape?
  • Can I work out the missing side from a compound shape using the measurements provided?