Choose an efficient way to decompose a compound shape to calculate the area
Lesson details
Learning outcome
I can choose the most effective way to decompose a shape into rectangles in order to calculate the area.
Key learning points
- Different methods for finding the area of compound rectilinear shapes will work in different situations.
- Compound rectilinear shapes can be split in different ways in order to calculate the area.
- Compare different methods to decompose shapes and decide which is the most efficient.
Keywords
Compound - A compound shape is made up of two or more shapes.
Common misconception
That a shape always has to be split into smaller shapes in order to calculate the area.
Show different ways to calculate area using the same shape. It can be split in different ways, completed and an area subtracted or a part cut and fitted into a gap.
Teacher tip
This lesson explores different ways to calculate the area of the same shape. The aim is that pupils think about the shape to decide which the most efficient strategy will be. This will include splitting shapes into smaller ones but consider subtraction strategies and rearranging shapes.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1. x 9 = 63
Q2.This compound shape is made from a large square and a smaller rectangle. Which multiplication facts could you use to help find the total area of this shape?
Q3.Which of these is NOT a compound rectilinear shape?
Q4.Which of the statements are true?
Q5.What is the total area of this compound shape?
Q6.What is the total area?
Assessment exit quiz
6 Questions
Q1. A shape is made up of two or more shapes. Complete the statement.
Q2.True or False.
This is the only way to split the compound shape into two rectangles.
Q3.What is the length of the missing side?
Q4.Match the image to the strategy.
Q5.Which calculation would you use to find the area of this shape in the way it has been split into rectangles?
Q6.Which pair of multiplications will help calculate the area of this compound rectilinear shape?
To help you plan your 5 maths lesson on: Choose an efficient way to decompose a compound shape to calculate the area, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 5 maths lesson on: Choose an efficient way to decompose a compound shape to calculate the area, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 2 maths lessons from the Link area of rectangles to multiplication unit, dive into the full primary maths curriculum, or learn more about lesson planning.