Year 5 · Mathematics
Converting metric units for Year 5: length, mass and capacity
The metric system is built on tens, hundreds and thousands, so converting between units is just multiplying or dividing by 10, 100 or 1000. The trick is knowing which way to go.
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Try asking: “How do I convert kilometres to metres?”
Key facts
- 1 cm = 10 mm
- 1 m = 100 cm
- 1 km = 1000 m
- 1 kg = 1000 g
- 1 L = 1000 mL
Which way?
Going to a smaller unit (like metres to centimetres), you need more of them, so multiply. Going to a bigger unit (like grams to kilograms), you need fewer, so divide.
Worked examples
Convert 3.5 km to metres.
- Kilometres to metres is going to a smaller unit, so multiply by 1000.
- 3.5 × 1000 = 3500.
Answer: 3500 m
Convert 450 cm to metres.
- Centimetres to metres is going to a bigger unit, so divide by 100.
- 450 ÷ 100 = 4.5.
Answer: 4.5 m
Convert 1500 g to kilograms.
- Divide by 1000: 1500 ÷ 1000 = 1.5.
Answer: 1.5 kg
Common mistakes to watch for
- Multiplying when you should divide — check that the answer makes sense (450 cm can't be 45 000 m!).
- Mixing up 100 and 1000 for metres and kilometres.
Practice questions
Try these, then reveal the answers. For more questions with hints, use the tutor.
1. Convert 6 km to metres. (Just the number.)
Show answer
6000
2. Convert 3.2 m to centimetres. (Just the number.)
Show answer
320
3. Convert 750 mL to litres. (Just the number.)
Show answer
0.75
4. Convert 4.5 kg to grams. (Just the number.)
Show answer
4500
5. Convert 85 mm to centimetres. (Just the number.)
Show answer
8.5