lesson
Not every conversion uses one hundred
1 · Learn
Time uses different relationships from decimal metric units: 1 hour is 60 minutes, not 100. A decimal part of an hour must be converted using sixty minutes per hour. For capacity, 1 litre is 1,000 millilitres.
Write the relationship before calculating and check the size. A quantity expressed in smaller units has a larger numerical count, but the actual duration or capacity has not changed.
2 · Worked example
1.25 hours is 1 hour plus a quarter of 60 minutes, or 75 minutes. It is not 1 hour 25 minutes. Also 0.375 litres is 375 millilitres.
3 · Your turn
Convert 2.4 hours to minutes and 2,650 ml to litres.
Check your answer
144 minutes; 2.65 litres.
4 · Apply your learning
Represent a quarter, a half and three quarters of an hour on a timeline, then compare decimal and minute forms.
Adult guidance and safety
Ask the learner to explain the method and check it using a different representation. Supply place-value grids, fraction strips, accurate diagrams and measuring tools where needed. These examples need varied practice; a short correct answer alone does not establish 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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