Measuring Time
Maths: Year 3 & 4 National Curriculum, topic 2.5.6
Measuring Time
We need to be able to measure and calculate with time to work out how long something takes or what time something will happen.
Duration
- Duration means how long something takes or lasts.
- A school starts the day at 9am.
- The first morning session lasts until breaktime at 10:20 am (twenty minutes past ten in the morning).
- Work out the duration of the first session.
Answer
- Counting on is a good way to calculate how long it is from one time to another.
- From 9am to 10am is 1 hour.
- From 10am to 10:20 is 20 minutes.
- The duration of the first session is 1 hour and 20 minutes.
- We don't write this as 1:20 as duration is an amount of time, not a time of day.
Using duration
- If we know what time something starts and how long it takes (the duration), we can work out when it will end.
- A car journey takes 2 hours and 10 minutes.
- The journey starts at 2:15pm (quarter past two in the afternoon).
- When will the journey end?
Answer
- Count up the hours first.
- 2 hours + 2 hours = 4 hours
- Count up the minutes.
- 15 minutes + 10 minutes = 25 minutes
- The journey will end at 4:25pm (twenty-five past 4 in the afternoon).
Adding up minutes
- Sometimes the minutes add up to more than 60.
- This means we need to think about hours and minutes.
- 60 minutes = 1 hour.
- 120 minutes = 2 hours.
- 70 minutes = 1 hour and 10 minutes.
Test yourself on Measuring Time
A movie lasts 120 minutes and finished at 11:00 pm. What time did the movie start?