Perimeter of Rectangles
This topic covers 4 learning steps, guiding your child from the basics through to confident problem-solving. Each step includes a worked example and adaptive practice questions.
What Your Child Will Learn
- What Is Perimeter?
Understand perimeter as the distance around a shape - The Perimeter Formula
Use P = 2(l + w) for rectangles - Find Missing Sides from Perimeter
Given perimeter and one side, find the other - Challenge — Perimeter & Area Combined
Solve problems involving both perimeter and area
Worked Example
Master Builder says:
Master Builder needs a fence around a plot 5 m long and 3 m wide. How much fencing?
- Add all four sides: 5 + 3 + 5 + 3.
- That is 5 + 3 + 5 + 3 = 16 m.
- Perimeter = 16 m.
Answer: 16 m
Common Mistakes
- Only adding two sides instead of all four (e.g. adding length + width and stopping, giving half the perimeter)
A rectangle has 4 sides. The perimeter is the total distance around ALL sides: length + width + length + width, or 2 × (length + width). Walk around a real rectangle (like a table) to reinforce "all the way round." - Confusing perimeter with area (multiplying instead of adding)
Perimeter is the distance AROUND the edge — you ADD the sides. Area is the space INSIDE — you MULTIPLY. Think: "Perimeter = path around the edge (add), Area = space inside (multiply)."
Tips for Parents
- Walk the perimeter of a room together, counting steps. "How many steps all the way around the kitchen?"
- Use string or ribbon: cut a piece the same length as the perimeter of a book. Then lay it out straight — that is how far it is around the book.
- Measure the length and width of different rectangles (books, tables, phones) and calculate the perimeter of each.
- Set a challenge: "Can you draw two different rectangles that both have a perimeter of 20 cm?" This deepens understanding.
Key Words
- Perimeter — The total distance around the outside of a shape.
- Length — The longer side of a rectangle.
- Width — The shorter side of a rectangle.
- Formula — A mathematical rule — the perimeter formula for a rectangle is 2 × (length + width).
Where This Fits
Before this topic: Children should measure lengths accurately in cm and m and add numbers confidently.
After this topic: Perimeter of rectangles leads to calculating the perimeter of irregular shapes, and understanding the relationship between perimeter and area.
How MathCraft Teaches This
In MathCraft, Perimeter of Rectangles is taught through the Geometry & Shape adventure track. Your child follows guided lessons with friendly characters, works through examples step by step, then practises with questions that adapt to their level.
The adaptive engine tracks mastery across all 4 steps, revisiting concepts your child finds tricky and advancing when they're ready. Parents can see detailed progress in the Parent Dashboard.
Practise Perimeter of Rectangles with MathCraft
Step-by-step lessons, worked examples, and adaptive practice — all wrapped in an adventure game your child will love.
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