Perimeter, area and volume
Around, on top and inside: three ways to measure a shape, with easy formulas. Read one step, play with it, then tap “I understand this”.
Perimeter: the length around
The perimeter of a rectangle is all four sides added. Because opposite sides are equal, you can also say: 2 × (length + width).
Walk around the rectangle
Change the length and width.
Area: square centimetres
We measure area in square units: a square of 1 cm by 1 cm is 1 cm². In a rectangle: area = length × width.
Fill the rectangle
Change the rectangle and look at the formula.
The length says how many squares fit in one row. The width says how many rows there are. Rows × squares in each row = all the squares.
Volume: cubes inside
Volume is how much space a 3D object takes up. We count cubes of 1 cm × 1 cm × 1 cm = 1 cm³. For a box: volume = length × width × height.
Build a box
Change the length, width and height.
Volume counts cubes, and a cube has three directions: long, wide and high. That is why the little ³. Area has only two directions (cm²), and a length just one (cm).
Which one do you measure?
Perimeter, area or volume?
Choose what you would measure.
Correct: 0Look at the unit: cm is perimeter (a length), cm² is area, cm³ is volume.
Check yourself
- Perimeter = around (cm). Rectangle: 2 × (l + w).
- Area = l × w, in cm².
- Volume = l × w × h, in cm³.
- Make the units the same first. 1 000 cm³ = 1 ℓ.
Write these points in your maths book. Read them again the night before the test.
Quick questions
Tap an answer. If you get one wrong, read why and go back to that step. You get new questions every time.
You ticked all 4 steps! Now you are ready for the quiz.- Practice sheet for this classQuestions + memo · 2 A4 pagesPractice sheet
- Measurement9 pages · PDFPaperMemo
Ready for more? The Grade 5 measurement quiz gives you new questions every time.
- One step a day is enough. Ten calm minutes work better than an hour the night before the test.
- Work out together how many tiles your bathroom floor needs, or how many sugar cubes fit in a box.
- Ask your child to tell you the rule in their own words. If they can explain it, they understand it.
- The ticks (“I understand this”) are saved on this device only. We never ask for names or emails.
Follows CAPS for Grade 5 Maths. Always check your teacher’s notes and textbook too.