Year 3 measurement is about moving between units: 1 metre is 100 centimetres, 1 kilogram is 1,000 grams and 1 litre is 1,000 millilitres. Children convert, compare mixed measures and add lengths and capacities.
What your child will learn
- Convert between m and cm, kg and g, l and ml, and cm and mm
- Write mixed measures like 1 m 35 cm in a single unit
- Compare measures given in different units
- Add lengths and capacities, including with regrouping
Same unit first
To compare 1 m and 85 cm, change them into the same unit: 1 m is 100 cm, so it is longer. Many mistakes come from comparing the numbers alone — 85 looks bigger than 1!
Watch the zeros
1 m 5 cm is 105 cm, not 15 cm. Thinking “1 metre is 100 centimetres, plus 5 more” keeps the place value right.
Example questions
Here are a few questions like the ones in the first quest. Can you solve them?
1. 80 mm is how many centimetres?
Show answer
Answer: 8. Every 10 mm makes 1 cm. 80 ÷ 10 = 8, so it is 8 cm.
2. How many grams are there in 5 kilograms?
Show answer
Answer: 5000. 1 kg = 1000 g, so 5 kg = 5 × 1000 = 5000 g.
3. How many centimetres are there in half a metre?
- 10
- 50
- 25
- 100
Show answer
Answer: 50. 1 m = 100 cm, and half of 100 is 50.
Tips for grown-ups
- Measure your height in metres and centimetres, then in centimetres only.
- Compare drink bottles: which holds more, 500 ml or 1 litre?
- Weigh baking ingredients in grams and talk about how close they are to a kilogram.