Someone has to pay for the paint. Before anybody buys a tin, a roll of turf or a metre of fencing, somebody measures the space — and the measurement decides the bill.
Today you take the first real measurements of your own project space. Those numbers go straight into your Maths Portfolio and feed the Collecting stage of MA1 KA1.
By the end of this lesson you will have a sketched outline of your space with length, width, perimeter and area written on it, all in metres.
Perimeter is the distance around the edge. Area is the surface inside. They answer different questions and they are bought in different units, so mixing them up costs money.
| Concept | Why it matters | Example |
|---|---|---|
| Perimeter — the total distance all the way around the edge of a space, found by adding every side | It is what you buy by the metre: fencing, skirting, edging, cable | A 6 m by 4 m yard needs 6 + 4 + 6 + 4 = 20 m of fencing |
| Area — the flat surface inside a shape, found for a rectangle by length × width, measured in square metres (m²) | It is what you buy by the square metre: paint, turf, paving, flooring | The same yard takes 6 × 4 = 24 m² of paving |
| cm to m — there are 100 cm in 1 m, so divide centimetres by 100 to get metres | Tapes often read in centimetres; suppliers quote in metres. Convert before you multiply | A wall measured as 420 cm is 420 ÷ 100 = 4.2 m on the order |
Look at the yard on the board. Perimeter and area are both shown. Notice they use different units — metres for the edge, square metres for the floor.
Watch the board first as the class works each size together. The teacher (or one nominated student) runs every challenge on the shared screen. You are not dragging on your own device during the class run.
For each size the board shows, work perimeter and area in your head or on paper before anyone taps Check:
Notice two things as the sizes change: doubling one side doubles that pair’s contribution to the perimeter and doubles the area; changing length and width together changes the area much faster than the perimeter.
If your room has 1:1 devices, you may retry the same challenges on your own screen after the class run. That is optional extension only.
Use the project space you named earlier in this unit. If you are not sure, or if that space is not a plain rectangle today, measure the cloakroom, a desk block, or the rectangle the teacher gives your group instead.
First, conversion warm-up on the board with the class (no tapes yet). Convert these three lengths to metres by dividing by 100: 350 cm, 480 cm, 125 cm. Keep the rule visible: convert first, calculate second, unit last.
Then, in threes, measure your rectangle. One holds the tape, one calls the measurement, one writes it down — then swap so everyone measures at least once.
Checkpoint 1 — stop and show the teacher before you calculate:
Checkpoint 2 — only after Checkpoint 1 is ticked:
Keep the tape tight and read at eye level. A slack tape is the most common way a measurement goes wrong.
Checkpoint 1: length and width to the nearest cm, then in metres (cm ÷ 100) — show the teacher before calculating. Checkpoint 2: perimeter, area in m², and a labelled sketch. Show every step of the working.
Work through these in order:
Your measurements are only portfolio evidence once they are written up so somebody else can follow them. Copy your figures onto this portfolio page, show the working for both calculations, and finish with the sentence that says what the numbers mean.
Instructions: Write every row down the page. Show the working, not just the answer, and put the unit after every figure. Sketch the outline underneath and label each side. End with one sentence saying what your area figure would let you order for this space.
Work each row in order onto a fresh page in your Maths Portfolio. Show the working, not just the answer.
Write these down the page, leaving room under each for your answer:
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