Year 4 - Maths
Know that perimeter is measured in units of length and can be found by counting or measuring units
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 know that perimeter is measured in units of length and can be found by counting or measuring units.
Key Notes
- Perimeter is measured in units of length.
- Perimeter can be counted if shapes are presented on squared paper.
- Perimeter can be measured using a ruler.
Vocabulary To Learn
- Perimeter: The distance around a two-dimensional shape.
- Unit: The unit of one of something that defines the 'one' you are counting in.
Common Mistakes To Avoid
- Pupils may count a side twice, or miss a side, if they do not remember where their starting point was on the shape when counting the perimeter.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
Perimeter is measured in units of length. Perimeter can be counted if shapes are presented on squared paper.
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 count a side twice, or miss a side, if they do not remember where their starting point was on the shape when counting the perimeter. Correction: Encourage pupils to mark a starting point, or use dots to mark the units they have counted.
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 can be calculated by adding together the side lengths of a 2D shape 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.