lesson
Use the stated units
1 · Learn
Metric conversions use relationships such as 1 km = 1,000 m, 1 m = 100 cm, 1 cm = 10 mm, 1 kg = 1,000 g and 1 litre = 1,000 ml.
Convert to matching units before combining measures. A smaller unit needs a larger count for the same amount. 2.5 litres is 2,500 ml, not 250 ml.
2 · Worked example
I add 1.25 m and 85 cm by converting to centimetres: 125 + 85 = 210 cm, or 2.1 m.
3 · Your turn
Convert 3.6 km to metres and 450 ml to litres. Find 2.4 kg − 650 g.
Check your answer
3,600 m; 0.45 litres; 1.75 kg or 1,750 g.
4 · Apply your learning
Estimate and measure safe objects, record units and check conversions using place value.
Adult guidance and safety
Model the calculation or measurement before relying on a procedure. Explain estimates, units and checks. Use a ruler/protractor and suitable diagrams where needed; text examples alone do not establish practical skill or fluency.
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Check a calculation · Year 5 onward
Use this only when your teacher or adult allows a calculator for the task. Show your thinking first. It does not replace mental or written arithmetic and does not mark your lesson answer.
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