Area — South Australian Year 4 Maths
Measuring area with tiles and other informal units, comparing and ordering areas, square centimetres and square metres, and rectangles on a grid. Four subtopics and 80 questions with answers, aligned to AC9M4M02.
Area in South Australian Year 4
Area is the amount of flat surface a shape covers. This topic starts by covering shapes with equal tiles and counting them, then moves to comparing and ordering areas, the formal units square centimetres and square metres, and finding the area of a rectangle by multiplying its rows by the squares in each row.
The four subtopics below are measuring area with informal units, comparing and ordering areas, measuring area in square centimetres and square metres, and finding the area of rectangles using a grid. Area is one of the 20 topics in South Australian Year 4 Maths and sits in the Measurement strand. All four subtopics come under Australian Curriculum code AC9M4M02, which also covers perimeter. Counting rows of squares leads to the length-times-width rule, which students start using here and rely on in later years.
Subtopics
Area: common questions
What is area?
Area is how much flat surface a shape covers. You measure it by covering the shape with equal units, with no gaps and no overlaps, and counting them. A tabletop covered by 5 rows of 9 placemats has an area of \(5 \times 9 = 45\) placemats.
Why do the units have to be the same size?
If some units are bigger than others, the count no longer tells you how much surface is covered. With equal units, more units always means more area. It also explains why a surface needs more small tiles than large ones, so always say which unit you counted.
What are square centimetres and square metres?
A square centimetre is a square 1 cm long and 1 cm wide, written \(\text{cm}^2\). A square metre is a square 1 m long and 1 m wide, written \(\text{m}^2\). Use square centimetres for small surfaces like a book cover, and square metres for big ones like a bedroom floor or a lawn.
How do you find the area of a rectangle on a grid?
Count the squares in one row, count the rows, then multiply. A rectangle with 6 rows of 7 squares covers \(6 \times 7 = 42\) squares, so on a centimetre grid its area is \(42\text{ cm}^2\). At home, draw rectangles on squared paper and check each multiplication by counting.
Which curriculum codes cover Area in South Australian Year 4?
All four subtopics come under Australian Curriculum code AC9M4M02, the Year 4 content on ways of measuring and estimating the area and perimeter of shapes and spaces, first with informal units such as tiles and then with square centimetres and square metres.