Year 4 - Maths
Know that perimeter can be calculated by adding together the side lengths of a 2D shape
Perimeter
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
In this unit pupil will learn perimeter as the distance around the edge of a 2D shape. They will learn perimeter is measured in units of length found by counting units and by calculating by adding the side lengths of a 2D shape.
Lesson Summary
You will learn to calculate the perimeter of a 2D shape by adding together the lengths of the sides.
Key Notes
- Perimeter is the sum of the side lengths of a 2D shape.
- If you measure the side lengths you can add them to calculate the perimeter.
- Mental and written methods can be used to calculate the perimeter of a 2D shape.
Vocabulary To Learn
- Perimeter: The distance around a two-dimensional shape.
Common Mistakes To Avoid
- Pupils may believe that there is only one way to add the perimeter of a shape - typically clockwise, starting from the top. This is untrue and will limit the efficiency of the arithmetic.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
Perimeter is the sum of the side lengths of a 2D shape. If you measure the side lengths you can add them to calculate the perimeter.
2. Use this key word in a maths sentence and explain it clearly. 'Perimeter'
The distance around a two-dimensional shape. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Pupils may believe that there is only one way to add the perimeter of a shape - typically clockwise, starting from the top. This is untrue and will limit the efficiency of the arithmetic. Correction: The lesson presents the idea of the side lengths being given in counters. The counters can then be re-ordered, for example so that a number bond to ten can be utilised. Using counters or sticky notes or similar may support pupils.
More Lessons In This Unit
- Calculate the side length of a regular polygon by division where the perimeter is known Study Guide
- Know that a regular polygon has sides that are the same length and angles that are the same size Study Guide
- Know that perimeter is measured in units of length and can be found by counting or measuring units Study Guide
- Know that the perimeter is the distance around a 2D shape Study Guide
- Know that the perimeter of a rectangle can be calculated by addition and multiplication Study Guide
- Know that unknown side lengths can be calculated from the perimeter and known side lengths Study Guide
- Solve problems involving the perimeter and side lengths of polygons Study Guide
- Understand that different shapes can have the same perimeter Study Guide
- Understand that the perimeter of a regular polygon can be calculated by multiplication Study Guide
Browse all guides in the Year 4 Maths guide library.