Mathematics
Intermediate
50 mins
Teacher/Student led
Learning Goals
Learning Outcomes
Lesson Files
+80 XP
What you need:
IWB/Projector/Large Screen
Metre stick
Masking tape

Estimating Then Measuring: Length

Estimate lengths of classroom objects and routes using a known anchor (the metre stick), then measure them and record how close your estimate was.

Teacher Class Feed

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    1 - Getting Started ~4 mins

    Illustration for Getting StartedPicture three spaces in our school: the corridor, the playground, and this classroom. If you had to bet, which one is the longest, and which one is the shortest?

    Here is the catch: you can't walk them, you can't pace them, you just have to picture them in your head and decide. Hands up when you've made your choice.

    👇 Mark your steps as done as you complete them.

    +5 XP

    2 - Watch and Notice ~9 mins

    Illustration for Watch and NoticeWatch closely. I'm holding our metre stick against three things in the room.

    First, the board rail. Before I lay the stick along it, who will estimate: how many metre sticks fit across it? Now watch as I lay the stick down and count.

    Next, this Maths book held lengthways. It's much shorter than a metre — so we measure it in centimetres along the stick instead.

    The rule today

    Last, the classroom door, top to bottom. Estimate first, then watch me check. Every time, the same rhythm: estimate first, measure second.

    👇 Mark your steps as done as you complete them.

    +10 XP

    3 - Set up Your Estimate Table ~2 mins

    COPYBOOK MOMENT

    Illustration for Set Up Your Estimate TableIn your maths copy, set up a three-column table ready to fill in. Head the columns 'estimate', 'actual', and 'difference'. Leave a few rows underneath so you have room for the lengths we measure together.

    +10 XP

    4 - Try It Together ~12 mins

    You're sitting in groups of four or five, and each group has one metre stick to share. Today we measure three lengths in our classroom together: the teacher's desk, the width of the door-frame, and the distance from the front wall to the back wall.

    Key point

    For each one, write your estimate in the 'estimate' column first. Then take turns: one person in the group lays the metre stick end-over-end while the others watch that it starts at zero and that there are no gaps, and call out the reading. Write the real length in the 'actual' column, then work out the difference and write it in the last column.

    Hands-on Task

    +15 XP

    5 - Class Challenge ~15 mins

    Going outside

    Groups of four or five, one metre stick, one copybook and one pencil per group. Assign each group one of the three routes. Take the class to whatever flat space your school has room in — yard, hall, or corridor. Before the lesson, mark three routes with chalk or masking tape: a Short route under 1 m, a Medium route around 5 m, a Long route 10 to 15 m.

    Materials

    • metre stick
    • copybook
    • pencil
    • chalk or masking tape (to mark routes)

    Plan

    1. Quickly check your own pace first: lay the metre stick down and take one normal step beside it to see how much of a metre your step covers.
    2. Write your estimate for your group's route in the estimate column — centimetres for the Short route, metres for the Medium and Long routes.
    3. Route A (Short, under 1 m): don't pace this one. Compare the line to half a metre stick or your Maths book held lengthways, then check with the metre stick.
    4. Route B (Medium, about 5 m) and Route C (Long, 10 to 15 m): pace it using your own step, then lay the metre stick end-over-end to find the actual length in metres.
    5. Write your actual measurement and work out the difference between it and your estimate, then read it out so it can be pooled on the board.
    If you can’t go out: indoor alternative

    If the yard is unusable, run the same Short / Medium / Long structure indoors — masking tape for the Short line, a stretch of the hall or classroom for the Medium, the full length of the corridor for the Long.

    +15 XP

    6 - What Did We Notice? ~4 mins

    MATHS TALK

    What made your best estimate of the day a good one? Was it comparing the length to something you already knew, like the metre stick or the door? Was it breaking a long route into smaller chunks? Which routes were hardest to estimate, and why?

    +10 XP

    7 - What's Next ~4 mins

    What we learned

    • A good estimate is a guess close to the truth, made by comparing to a length you already know.
    • We sharpen an estimate by measuring with a metre stick and finding the difference.
    • The difference tells us how close our estimate was.
    Coming up

    Next we look more closely at the smallest marks on a ruler and read lengths to the nearest millimetre.

    +5 XP
    Pupil practice
    Module 4 · Measures: Length, Mass, Capacity, Area, Volume Measures
    Lesson 49 · Estimating Then Measuring: Length
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