Overview

Duration: 45 minutes
Class: Year 4 (age 8-9)
Subject: Maths
Topic: Understanding and converting metres (m) to kilometres (km)
Curriculum Link:

• National Curriculum for England (Maths, Key Stage 2, Year 4)
  • Measurement: Convert between different units of measure (for example, kilometre to metre)
  • Solve problems involving converting from hours to minutes; minutes to seconds; years to months; weeks to days; kilometres to metres; grams to kilograms; litres to millilitres

Learning Objectives

By the end of this lesson, pupils will be able to:

• Recognise the relationship between metres and kilometres (1 km = 1000 m).
• Convert lengths from metres to kilometres and vice versa using place value understanding.
• Solve increasingly complex word problems involving conversions between m and km.
• Explain and justify their methods and reasoning when converting measurements.

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Success Criteria

I can:

• Explain how many metres are in a kilometre.
• Convert metres to kilometres by dividing by 1000.
• Convert kilometres to metres by multiplying by 1000.
• Explain why and how I converted the units using mathematical reasoning.
• Solve word problems that require conversion between metres and kilometres.

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Resources

• Whiteboard and marker
• Mini whiteboards and pens for pupils
• Place value charts
• Worksheet with activities increasing in difficulty
• Visual metre and kilometre measurement strips (to scale)
• Word problem cards
• Rulers or metre sticks

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Lesson Structure

1. Introduction (10 minutes)

Engagement:
Display a large poster showing a 1-metre stick and 1-kilometre signpost. Ask:

• "If I asked you to travel to school and told you it was 1 kilometre away, how far is that really?"
• Show a visual analogy, e.g., “Imagine walking 1000 metre sticks one after another – that’s 1 kilometre!”

Questioning:

• "How do you think metres and kilometres are related?"
• "If 1 kilometre is a big distance, how many metres do you think are in 1 kilometre? Explain your thinking."
• "What operation would you use to go from kilometres to metres? Why?"
• "How would you explain to a friend how to convert 5000 metres into kilometres?"

These questions encourage recall and reasoning (Bloom’s: Remembering, Understanding, Applying, Explaining).

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2. Modelling & AfL (10 minutes)

Modelling:

• Write on the board:

  • 1 km = 1000 m
  • 5000 m = ? km -> Show dividing by 1000: 5000 ÷ 1000 = 5 km
  • 3.2 km = ? m -> Show multiplying by 1000: 3.2 × 1000 = 3200 m

• Use a place value chart to model moving the decimal point when dividing or multiplying by 1000, reinforcing understanding of place value in measurement conversion.

AfL Opportunities:

• After modelling each conversion, ask pupils to explain why division or multiplication is used here (Targeted questioning).
• Use mini-whiteboards for pupils to show answers to quick conversions you say aloud (e.g., 1200 m to km, 4.5 km to m).
• Circulate and notice misconceptions — e.g., mixing up multiplying with dividing, or misplacing the decimal point.

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3. Addressing Common Misconceptions (5 minutes)

• Pupils often confuse whether to multiply or divide by 1000.
• Some believe 1 km = 100 m instead of 1000 m.
• Decimal place value shifts are misunderstood (e.g., thinking 3200 m = 3.2 m).
• Emphasise consistent use of place value charts for clarity. Visual aids here work best.

Ask pupils:

• "What mistakes might happen when converting 4500 m to km? How can we avoid them?"
• "Why can’t we just subtract 3 zeros instead of dividing by 1000?"

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4. Guided Practice - Increasing Complexity (15 minutes)

Task Stage	Description	Higher-order thinking focus
Stage 1 - Simple conversions (divide/multiply by 1000)	Convert: 3000 m to km, 2 km to m, 450 m to km, 5.7 km to m	Remembering, Applying
Stage 2 - Word problems with one-step conversions	"Sam ran 4000 metres. How many kilometres did he run?"	Understanding, Explaining
Stage 3 - Two-step problems involving conversions	"A track is 1500 m long. How many tracks would make 6 km?"	Applying, Analysing
Stage 4 - Explanation & reasoning task	"Explain how you convert 2500 m to km and why this method works."	Evaluating, Creating (forming explanations)

Task example for children to copy:

Example:
Convert 7200 metres into kilometres.
Since 1 kilometre = 1000 metres, divide 7200 by 1000.
7200 ÷ 1000 = 7.2 kilometres.
Therefore, 7200 metres = 7.2 kilometres.

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5. Plenary (5 minutes)

• Quick-fire questions to check understanding:

  • "What is 3500 m in km?" (Expected: 3.5 km)
  • "If you walk 2.4 km, how many metres have you walked?" (Expected: 2400 m)
  • "Explain to your partner how you would convert 450 m into km?"

• Invite 2-3 children to explain their reasoning to the class (peer learning).

• Refer back to the success criteria. Ask children to self-assess:

  • Which success criteria have I achieved?
  • What do I want to practise more?

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Key Whole Class Questions (targeting higher-order thinking)

Question (with Bloom’s level)	Purpose/Focus
"Why do we divide by 1000 when converting metres to kilometres?" (Understand)	To explain the mathematical relationship and operation used.
"How can place value help us in converting 4500 m into km?" (Apply)	To connect place value understanding with measurement.
"Can you think of a real-life situation where you would need to convert km to m or vice versa?" (Create)	To link maths learning to real-world application.
"If a number gets smaller when converting, what does this suggest about the unit sizes?" (Analyse)	To develop conceptual reasoning about units and scale.
"Explain a mistake someone might make when converting 3.5 km to metres and how they could avoid it." (Evaluate)	To assess understanding by identifying common pitfalls.

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Assessment for Learning (AfL) Points Integrated

• During Modelling: Use mini-whiteboards for quick checks on conversion calculations. Immediate verbal feedback to correct misconceptions.
• Questioning: Ask pupils to explain reasoning, correcting and probing understanding on the spot.
• Guided Practice: Observe and note mistakes or hesitation, provide targeted support or prompts.
• Plenary: Use self-assessment and peer explanation to reveal depth of understanding or identify gaps.

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Alignment with White Rose Maths Scheme

This lesson reflects the Spring Term, Year 4 block on Measurement - converting units of length, consistent with WRM approaches:

• Focus on place value and the effect of multiplying/dividing by powers of 10.
• Gradual progression of tasks from straightforward conversions to problem solving and reasoning.

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Summary

This lesson plan uses strong visual models, place value understanding, real-world context, and Bloom’s taxonomy to build deep conceptual understanding and independent reasoning about converting metres and kilometres. Through careful AfL integration and scaffolded tasks, all pupils can achieve success with measuring units, aligned with national standards and White Rose maths expectations.