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Cotmanhay Junior School

Safe, Happy Learning

Week 10-11 Converting units

National curriculum content


  • Convert between different units of metric measure (for example, kilometre and metre; centimetre and metre; centimetre and millimetre; gram and kilogram; litre and millilitre)
  • Understand and use approximate equivalences between metric units and common imperial units such as inches, pounds and pints
  • Solve problems involving converting between units of time
  • Use all four operations to solve problems involving measurements such as length, mass and money using decimal notation, including scaling


Lesson objectives


  1. Kilograms and kilometers
  2. Millimeters and milliliters
  3. Convert units of length
  4. Convert between metric and imperial units
  5. Convert units of time
  6. Calculate with timetables


 What we want children to know

  • How to use a range of equipment when measuring.
  • Understand which unit of measure to use.
  • How to convert between different units of metric measure.
  • How to convert between different units of imperial measure.
  • How to convert between different units of time.
  • Understand which operation to use when solving problems involving measurements.


What skills we want children to develop

Use knowledge to solve reasoning and problem solving questions such as:


Metric Units:

A 10 piece coin is 2mm thick.

Evie makes a pile of 10 pence coins worth £1.50.

What is the height of the pile of coins in centimeters?


Kilograms and Kilometers:

Amir buys 2,500 grams of potatoes and 2,000 grams of carrots.

Potatoes cost 78p.

Carrots cost £1.46.

He pays with a £5 note.

How much change does he get?


Converting Units of Time:

Teddy’s birthday is in March.

Amir’s birthday is in April.

Amir is 96 hours older than Teddy.

What dates could Teddy and Amir’s birthdays be?


Mathematical Talk

What does ‘kilo’ mean when used at the start of a word?

How would you convert a fraction of a kilometre to metres?

Would it be appropriate to measure your height in millimetres?

Which unit of measure would be best to measure; the height of a door frame, the length of a room, the width of a door?

Why do you think we still use imperial measures?

How precise should approximation be?

Is 0.75 hours the same as 75 minutes? Why or why not?