Understand the idea.
Equal units cover fairly
Measure area by covering the entire region with equal square units. Place them edge to edge without gaps or overlaps. Each square must be counted once, including the squares in the middle rather than just those around the edge.
Use the same-sized unit when comparing areas. Ten large squares and ten tiny squares cover different amounts of space even though their counts match. The unit size is part of the measurement.
Whole and partial squares
Count whole squares first, using equal rows to organise a rectangular grid. Then combine partial squares. Two exact half-squares make one whole square, so four half-squares contribute two square units.
On a curved or uneven boundary, parts may only look like halves. Pair those parts to estimate whole squares and say the result is about that many square units. Exact halves can be combined exactly; uncertain parts give an estimate.
See the method in action.
Equal rows
A rectangle covers 5 squares in each of 2 rows. Find its area.
Worked solution
- 1
Read the rows and columns.
Each row contains the same number of equal square units.
- 2
Count both complete rows.
The two rows cover the rectangle without any missing or repeated squares.
- 3
Express the area in square units.
The count measures surface covered rather than distance around the edge.
10 square units.
Putting halves together
A region covers 6 whole grid squares and 4 half-squares. Find its area.
Worked solution
- 1
Combine the four half-squares.
Every pair of equal half-squares makes one whole square.
- 2
Add the six whole squares.
The whole-square count and the combined parts account for the complete region.
- 3
Decide whether the result is exact.
The question gives exact half-squares, so 8 square units is exact rather than an estimate.
8 square units.
Try it yourself.
Check your understanding
What area is covered by 3 whole squares and 2 half-squares?
Show answer & reasoning
4 square units.
The two half-squares make one whole square. Add this to the three complete squares: square units.
Keep practising
6 worksheet questions · 8 marks
Read the questions online
- A fully shaded grid has 4 columns and 3 rows. Find the area.1 mark
- Find the shaded area on the supplied grid.1 mark
- A region covers 7 whole squares and 2 half-squares. Find its area.1 mark
- A region covers 4 whole squares and 6 half-squares. Find its area.1 mark
- Why must square units not overlap when measuring area?2 marks
- A curved region covers 9 whole squares and several pieces that together look like about 3 whole squares. Estimate its area.2 marks
Read the worked solutions
Equivalent correct methods earn the corresponding marks. Include units where asked.
- A fully shaded grid has 4 columns and 3 rows. Find the area.1 mark
square units.
12 square units. - Find the shaded area on the supplied grid.1 mark
Count the five shaded unit squares.
5 square units. - A region covers 7 whole squares and 2 half-squares. Find its area.1 mark
The two halves make 1 whole: .
8 square units. - A region covers 4 whole squares and 6 half-squares. Find its area.1 mark
Six halves make 3 wholes: .
7 square units. - Why must square units not overlap when measuring area?2 marks
Each part of the region should be counted once.
An overlap would count part of the region more than once. - A curved region covers 9 whole squares and several pieces that together look like about 3 whole squares. Estimate its area.2 marks
9 whole squares about 3 from pieces gives about 12.
About 12 square units.
Curriculum reference & lesson scope
Australian Curriculum v9 / SA Curriculum Mathematics 2026
Boundary/interior; measuring perimeter; covering/counting/estimating area; comparing shapes.
Official curriculum source ↗