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SavannahYear 8

Year 4 · Measures, time and graphs

Area, symmetry and 24-hour time

Find the area of rectilinear shapes by counting squares

20 minutes4 checks6 exit questionsNational curriculum objective

Lesson overview

What you'll learn in this lesson

Find the area of rectilinear shapes by counting squares

Key learning points

  • • Counting squares
  • • Lines of symmetry
  • • The 24-hour clock
  • • Working out how long

This lesson at a glance

  • 20 minutes
  • 19 parts to scroll through
  • 4 quick checks
  • No marked quiz yet
  • Gentle pace: short sittings with pauses

Words to know

rectilinearshapescountingsquaressymmetry

Scroll down — the lesson carries on below

Part 1 of 19 · Discover5%
1

Watch & discover

Part 1 of 19

Silent film

Watch first

Area, symmetry and 24-hour time

Measuring round the edge, covering the inside, then reading the clock.

Read the film in words (English) ↓

What the film shows

  1. A finger traces the edge of a rectangle while the perimeter total counts up.
  2. The same rectangle fills with unit squares to show its area.
  3. Units convert on screen: centimetres to metres, grams to kilograms, millilitres to litres.
  4. A 12-hour clock and a 24-hour clock show the same moment side by side, then a bar chart is read off.
  5. The perimeter and unit-swap practicals for this unit repeat all of this with a tape measure.

Do it for real

The practicals below use what the film shows, with a full method you can follow at home.

Same perimeter, different areaGrams, millilitres and a fair biscuit test

In a nutshell

Find the area of rectilinear shapes by counting squares

2

What you already know

Part 2 of 19

Before we start

What you already know

You can measure in centimetres and read an analogue clock to five minutes.

3

Key words

Part 3 of 19

Key words

Words you'll need today

area
The amount of surface a shape covers, measured in squares.
rectilinear
A shape whose sides are all straight and meet at right angles.
line of symmetry
A fold line where both halves match exactly.
4

Learning cycle

Part 4 of 19

Learning cycle 1 of 2

Part 1 — Area and symmetry

A short piece of teaching, then a check to make sure it has landed.

5

Explore the idea

Part 5 of 19

Learn

Counting squares

Area is how much space a shape covers. On squared paper, count the squares inside it. A rectangle 5 squares across and 3 down covers 15 squares. For an L-shape, split it into two rectangles, find each area, then add them together.

6

Explore the idea

Part 6 of 19

Learn

Lines of symmetry

A line of symmetry is a fold where both halves land on top of each other. A square has 4, a rectangle has 2, an equilateral triangle has 3, and a circle has endless lines. Turning a shape sideways does not change how many it has — the lines turn with it.

7

Quick check

Part 7 of 19

Quick check

A rectangle is 6 squares by 4 squares. Its area is...

8

Quick check

Part 8 of 19

Quick check

How many lines of symmetry does a rectangle have?

9

Reset break

Part 9 of 19

Pause

That's sitting 1 of 2 done

Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.

Stop here for now
10

Learning cycle

Part 10 of 19

Learning cycle 2 of 2

Part 2 — Telling the time

A short piece of teaching, then a check to make sure it has landed.

11

Explore the idea

Part 11 of 19

Learn

The 24-hour clock

After 12:59 in the afternoon, 24-hour time keeps counting: 1 pm is 13:00, 5 pm is 17:00, 9 pm is 21:00. Just add 12 to any afternoon or evening hour. Midnight is 00:00 and it is always written with four digits.

12

Explore the idea

Part 12 of 19

Learn

Working out how long

To find how long from 14:35 to 16:10, count on: 25 minutes to 15:00, one hour to 16:00, then 10 minutes. That is 1 hour and 35 minutes. Counting on in friendly jumps is easier and safer than subtracting times in columns.

13

Quick check

Part 13 of 19

Quick check

4 pm in 24-hour time is...

14

Quick check

Part 14 of 19

Quick check

How long from 09:20 to 10:05?

15

Common mix-ups

Part 15 of 19

Common mix-ups

Things people often get wrong

  • Counting the edge squares instead of the squares inside.
  • Thinking a rectangle has 4 lines of symmetry like a square.
  • Writing 7 pm as 07:00 instead of 19:00.
16

Challenge round

Part 16 of 19

Game · Sort it

Which of these are true?

Drag each card into the right column. Tap a card first if dragging is fiddly.

True

Not true

17

Challenge round

Part 17 of 19

Game · Fill the gaps

Finish the sentences

Choose the word that belongs in each gap.

On squared paper, count the ____ inside it.

A line of ____ is a fold where both halves land on top of each other.

After 12:59 in the afternoon, 24-hour time keeps ____: 1 pm is 13:00, 5 pm is 17:00, 9 pm is 21:00.

18

Mastery quiz

Part 18 of 19

No quiz for this one

This lesson has no marked quiz attached yet.

19

Lesson round-up

Part 19 of 19

Lesson round-up

Ready when you are

Quiz score

Not sat

Games

Not played

Points this lesson

0

Best run

0 in a row

Luna: 0 out of 4 on the practice checks. Only if you feel up to it — one more?

Ask Luna

Do the work

Your written work for this lesson

This is the part you'd do in your book at school. Pick the pieces below, write here or on paper, and photograph anything you draw or work out.

Article

The cost of a school trip

A school is planning a trip to a wildlife park. The coach costs £480 however many people go. Entry costs £9.50 for each pupil and each adult goes free. The school says every pupil must pay the same amount, and the trip must not lose money.

If 60 pupils go, the coach works out at £8 each, so the total for each pupil is £17.50. If only 40 pupils go, the coach works out at £12 each, so the price rises to £21.50. The teacher explains that the coach is a fixed cost and the entry is a cost per person — which is why the price per pupil changes when the number changes.

The school decides to charge £20 and to use anything left over for a second trip later in the year.

Written for Good Learning Co.

Reading questions

  1. Work out the total cost of the trip if 50 pupils go.
  2. Show why the price per pupil falls when more pupils go, using numbers.
  3. At £20 each, how many pupils must go before the trip makes money? Show your working.

  • Working out

    Working out

    Do the practice questions on paper, showing every step — not just the answer. Mark them yourself and circle anything you got wrong.

    10–15 questions

  • Worked example, explained

    Writing

    Copy one question out and write underneath, in words, why each step works.

    1 question, 4–5 sentences

  • Problem in words

    Working out

    Write your own real-life problem that uses today's method, then solve it.

    1 problem + solution

Saved as you type.

Part 1 of 19 · Watch & discover

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