Count the square units
A shape covering 8 equal squares has an area of 8 square units.
Count the inside squares, not the outside edge.
Year 4
Find the area of rectilinear shapes by counting squares
Find area by counting how many equal square units cover the surface of a rectilinear shape.
Lesson overview
Measurement
Area measures how much surface is covered. We can find the area of a rectilinear shape by counting the equal squares inside it. Each square is one square unit.
Area is inside, perimeter is outside
Area counts inside squares while perimeter measures around the outside.
Area and perimeter are different ideas.
Equal squares matter
The squares must all be the same size for the count to be fair.
count equal squares
measure around edge
Equal squares make the measurement reliable.
Worked example
A rectilinear shape covers 12 equal squares. What is its area?
- Look at the inside of the shape.
- Count the equal squares that cover it.
- There are 12 squares.
- So the area is 12 square units.
Round 1: Learn it
Count the inside equal squares carefully and keep area separate from perimeter.
Finish this round to unlock Round 2: Show you know it.
Question 1
A shape covers 6 equal squares. What is its area?
Question 2
Which part of the shape do we count for area?
Question 3
A rectilinear shape covers 14 equal squares. Write the number only.
Question 4
Which idea matches area?
count square units
add outer sides
Question 5
A shape covers 9 equal squares. What is its area?
Common mistakes
Watch for these as you work through the lesson.
- Counting the edge instead of the inside squares.
- Mixing up area and perimeter.
- Forgetting that the squares must be equal in size.
Related topics
These ideas connect closely to this lesson.
- Measure and calculate the perimeter of a rectilinear figure in centimetres and metres.
- Convert between different units of measure.