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Converting Metric Units: An Island Trek with Milli

Converting Metric Units: An Island Trek with Milli

Learn how converting metric units works for km, m, cm, mm, g, kg, l and ml, then solve measure, money and recipe-scaling problems with Milli.

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What you'll learn

  • Why km and m, kg and g, and l and ml all use 1,000
  • That 1 m = 100 cm, 1 cm = 10 mm and 1 m = 1,000 mm
  • When to multiply and when to divide to change units
  • Why the placeholder zero matters: 2 km 50 m is 2.05 km
  • How to solve measure and money problems by lining up decimal points
  • How to scale recipe amounts up and down by multiplying or dividing

Chapter by chapter

  1. Kilometres and metres: 1 km = 1,000 m Free to try

    Year 5 maths · 1

  2. Metres, centimetres and millimetres: 1 m = 100 cm, 1 cm = 10 mm

    Year 5 maths · 1

  3. Grams and kilograms: 1 kg = 1,000 g

    Year 5 maths · 1

  4. Litres and millilitres: 1 l = 1,000 ml

    Year 5 maths · 1

  5. Measure problems: add, subtract, multiply and divide with decimals and money

    Year 5 maths · 2 Year 5 maths · 1

  6. Scaling measures: multiply and divide to make amounts bigger or smaller

    Year 5 maths · 2 Year 5 maths · 1

  7. Summit Challenge (10 questions) (10 questions)

What the chapters cover in the national curriculum in England:

  1. Year 5 maths: Convert between different units of metric measure
  2. Year 5 maths: Use all four operations to solve problems involving measure using decimal notation, including scaling

About this adventure

Converting Metric Units is an interactive maths game that teaches children aged 8–11 to convert between kilometres and metres, metres, centimetres and millimetres, grams and kilograms, and litres and millilitres. It follows the Year 5 maths curriculum in England, and Milli the meerkat reads every step aloud with captions.

Children build each unit for themselves. They walk a 1 km trail in 100 m steps, zoom into a ruler to count millimetres, load 100 g weights onto a scale and pour cups into a litre jug. A conversion machine asks whether to multiply or divide, and a place value chart shows the digits sliding while the decimal point stays still.

Next, children solve measure and money problems with decimals by changing to the same unit and lining up the decimal points. They also scale recipes up and down. A 10-question summit challenge ends the game.

Questions and answers

How do you convert kilometres to metres?

To convert kilometres to metres, multiply by 1,000, because 1 kilometre is 1,000 metres. So 3 km is 3,000 m and 2.5 km is 2,500 m. To change metres back into kilometres, divide by 1,000, so 4,000 m is 4 km.

How many millimetres are in a centimetre and in a metre?

There are 10 millimetres in 1 centimetre and 1,000 millimetres in 1 metre. A metre is 100 centimetres and each centimetre holds 10 millimetres, so 100 × 10 = 1,000.

When do you multiply and when do you divide when converting units?

Multiply when you change to a smaller unit and divide when you change to a bigger unit. You need more of a smaller unit to make the same amount, so 2 kg becomes 2,000 g, while 750 ml becomes 0.75 l.

What age is this converting units game for?

The game is for children aged 8 to 11 and is pitched at Year 5 maths in England, where children learn to convert metric units. Every line is read aloud with captions, so less confident readers can follow along.

What does the converting units game include and how long does it take?

The game has six chapters, each with an animated introduction, hands-on activities, typed practice and a three-question check. It also has a 10-question summit challenge and an optional warm-up on multiplying and dividing by 10, 100 and 1,000. Playing everything takes about 80 minutes.

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