Area and Perimeter: Area by Counting Squares — Year 4 Lesson Plan
National Curriculum: Mathematics — Measurement, Year 4: find the area of rectilinear shapes by counting squares; notes and guidance: relate area to arrays and multiplication
Overview
The third of four Area and Perimeter lessons. Pupils learn that area is the amount of flat surface a shape covers. They find the area of rectangles and other rectilinear shapes by counting squares, record it in square centimetres, and use rows and columns, like an array, to count the squares in a rectangle more quickly.
Area and Perimeter: Area by Counting Squares learning objectives
- Explain that area is the amount of flat surface a shape covers.
- Find the area of rectilinear shapes by counting squares.
- Record area in square centimetres (cm²).
- Use rows and columns, like an array, to count the squares in a rectangle quickly.
Success criteria
- I can explain what area means.
- I can find the area of a shape by counting squares.
- I can write area in square centimetres (cm²).
- I can count the squares in a rectangle quickly using rows and columns.
Key Vocabulary
Suggested Lesson Structure
Ask: which covers more of the table, an exercise book or a sheet of A4 paper? Pairs cover each with the same-sized square tiles or sticky notes and count. Introduce area as the amount of surface a shape covers, measured by counting squares of the same size.
Show a 1 cm square and explain that its area is one square centimetre, written 1 cm². On centimetre-squared paper, count the squares in a 6 by 4 rectangle one at a time, marking each square, to get 24 cm². Then count by rows: 4 rows of 6 is 24, just like a 4 × 6 array. Show an L-shape and count it carefully row by row, adding the rows of different lengths. Contrast area (the squares inside) with perimeter (the distance around the edge).
Pairs find the areas of rectangles and L-shapes on squared paper, using rows to count quickly and then checking by counting one by one. Discuss: which way was quicker? Which was more accurate?
Pupils draw three different rectilinear shapes on centimetre-squared paper, each with an area of 12 cm², and label each one. Challenge: draw as many different rectangles as you can with an area of 24 cm². How do they link to the 24 times-table facts?
Show two shapes on squared paper and ask which has the greater area. Pupils explain how they know, using the words area, square centimetres and rows.
Video for this lesson
Area by Counting Squares | Year 4 Area and Perimeter, Lesson 3 | KS2 Maths (No Narration)
Which shape covers more, square centimetres, counting squares one by one and then in rows like an array, and the area of an L-shape. Useful before pupils count on squared paper. Ends with a three-question quiz.
Watch on YouTube →Support and extension for area and perimeter: area by counting squares
Support
- Give pupils a counter or pen to mark each square as it is counted.
- Start with rectangles of up to 3 rows before moving to larger shapes and L-shapes.
- Build each rectangle with square tiles first, then draw it on squared paper.
Extension
- Draw every rectangle with an area of 24 cm² and link each one to a multiplication fact.
- Draw an L-shape with an area of 20 cm² and explain how you checked it.
- Find the area of a shape that is made of two rectangles joined together by adding their areas.
Check for understanding
Quick questions for the plenary or an exit ticket. Tap a question to see the answer.
1. What is area?
Answer: The amount of flat surface a shape covers.
2. A rectangle has 4 rows of 6 squares. What is its area?
Answer: 24 cm² (4 × 6).
3. What does cm² mean?
Answer: Square centimetres: the number of 1 cm squares that cover the shape.
4. An L-shape has rows of 5, 5, 2 and 2 squares. What is its area?
Answer: 14 cm².
Resources you will need
- Centimetre-squared paper
- Square tiles or sticky notes of the same size
- A 1 cm square cut out to show 1 cm²
- Shape cards with rectangles and L-shapes
Common Misconceptions
- Counting a square twice or missing one. Mark each square as it is counted, or count in rows.
- Counting the squares around the edge instead of all the squares inside.
- Writing cm instead of cm² for area.
- Thinking a longer or taller shape must have a greater area. Count the squares to compare.
Prior Knowledge
Pupils should already be able to:
- Recall multiplication facts and use arrays to show multiplication (Autumn 1, times tables to 12).
- Know what perimeter is and how to find it (lessons 1 and 2).
- Recognise rectangles, squares and right angles.
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