The idea in brief. Area of a rectangle is length × breadth; area of a square is side × side. Area uses square units. Equal perimeters do not guarantee equal areas. In the lesson. You have found area by counting the square units a figure covers. Today, we will find the area of a rectangle or a square by multiplying. Area of a rectangle is length times breadth. Area of a square is side times side.
Lesson video, with the working
Area of a rectangle or square
2 min 56 s
The film teaches 3 questions in turn. Each question shows first; its working is written as the film explains it.
How do you answer area of rectangle and square questions in P3?
Once your child can count square units, the next step in Primary 3 is to see that a rectangle's squares sit in neat rows, so counting them is the same as multiplying.
What your child learns here
Once your child can count square units, the next step in Primary 3 is to see that a rectangle's squares sit in neat rows, so counting them is the same as multiplying. This page turns that idea into the rule length times breadth, with side times side for a square.
A rectangle on a grid is made of equal rows of squares, so its area is length × breadth.
A square has four equal sides, so its area is side × side.
Area is written in square units, such as cm² for small things and m² for floors and gardens.
Area and perimeter measure different things, and the answer must use the right kind of unit.
Two rectangles can have the same perimeter but different areas.
Does the answer make sense?
Every answer here is an area or a difference between two areas, so your child's answer ends in cm² or m², never plain cm or m. When the question asks how much greater, or how much floor is left uncovered, the answer must be smaller than the larger area being compared.
How to practise these questions
The Basic questions practise multiplying length by breadth for rectangles and squares. The Intermediate questions add stories that ask for area in square centimetres or square metres. The Challenge questions require your child to find a side first, or to compare two areas, before the answer is reached. When an area question is stuck, view its solution film and try once more later from Revision.
Questions parents ask
Is the area of a rectangle in the P3 syllabus? Yes. The Primary 3 syllabus lists the area of a rectangle or square, together with measuring area in square units, cm² and m². It does not include converting between cm² and m² at this level.
Should my child say breadth or width? School worksheets in Singapore usually say length and breadth for a rectangle, and the lessons here use the same words. Both mean the same distance, so a child who says width is not wrong, but using breadth keeps their working in step with the page.
Does my child need to memorise length times breadth? It helps, but it is better if they can also explain it. A rectangle on squared paper is rows of equal squares, so multiplying the rows by the squares in each row counts them all at once. A child who can say that can rebuild the rule whenever they forget it.
Why is area written in square centimetres? Area counts how many unit squares cover a shape, so its unit is a square: a square centimetre is a square 1 cm long on each side. Writing cm² instead of cm reminds your child that the answer counts squares, not the length of a side, which is how area stays separate from perimeter.
