Calculate missing dimensions in rectangles and compound rectilinear shapes

I can calculate missing dimensions in rectangles and compound rectilinear shapes.

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Year 5

Calculate missing dimensions in rectangles and compound rectilinear shapes

I can calculate missing dimensions in rectangles and compound rectilinear shapes.

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Share activities with pupils

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Lesson details

Key learning points

Division is used to calculate a missing dimension when the area and the other dimension are known.
Inverse operations are used to calculate missing dimensions when areas are known.
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.
Dimension - A dimension is a measurement of length in one direction. Width and height are examples of the dimensions of 2D shapes.

Common misconception

Applying known facts and strategies to solve problems involving division. Being able to break down a problem into steps when it comes to compound shapes.

Provide opportunities to discuss approaches and highlight the efficient strategies and approaches. Acknowledge that there is more than one way to solve a problem whilst focusing on efficient and effective strategies.

Make time to discuss problems with pupils and for pupils to talk to each other about the shapes. Draw attention to the strategies and approaches featured in the lesson. Model the thinking and steps needed when tackling missing dimensions in compound shapes so that pupils can apply it in their work.

Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).