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Let's recap on the words we can use to talk about time.

• There are 60 seconds in 1 minute.

• There are 60 minutes in 1 hour.

Duration is how long something lasts.

It's useful to be able to compare durations of time taken by different events.

For example, you could ask yourself:

• Which is the longest film?
• Which is the shortest journey?
• Is this TV programme longer or shorter than the other one?
• How much longer or shorter is it?

We can use an analogue clock (one with hands that shows each hour between 1 and 12) to work out different time durations - between each number is an interval of 5 minutes. We could also use a number line, a bit like the one below, to write our start time and then count on in 5 minute intervals to reach our end time.

Is the Science lesson longer, shorter or the same length as the Music lesson?

Science

• Start time: 3 o'clock PM
• End time: 25 past 3 PM

Music

• Start time: Half past 8 AM
• End time: 5 past 9 AM

Starting with Science, between 3 PM and 25 past three PM we can count 5 intervals of 5 minutes.

5 × 5 = 25

There is a duration of 25 minutes.

For Music, between half past 8 AM and 5 past 9 AM we can count 7 intervals of 5 minutes.

7 × 5 = 35

There is a duration of 35 minutes.

So we can say that the Science lesson is shorter than the Music lesson.

Let's look at the following table that shows the durations of time taken to fly to different cities.

Is the time taken to get to Paris longer or shorter than to New York?

The journey to Paris lasts from 15:15 to 16:40.

We can count on 1 hour from 15:15 to reach 16:15 and then add an extra 5 lots of 5 minutes to reach 16:40.

The total time is 1 hour and 25 minutes (5 × 5 = 20) or 85 minutes.

The journey to New York lasts from 07:25 to 10:15.

We can count on 3 hours from 07:25 to reach 10:25 and then subtract 2 lots of 5 minutes (2 × 5 = 10 minutes) to go back to 10:15.

The total time is 2 hours and 50 minutes or 170 minutes.

The time taken to get to Paris is shorter than to New York.

Which journey takes the greatest amount of time?

The duration of time we haven't worked out yet is the journey to London. This lasts from 11:00 to 11:52.

We can count 10 lots of 5 from 11:00 to reach 11:50 and then we can add on 2 extra minutes to reach 11:52.

(10 × 5) + 2 = 52 minutes.

If we compare this duration with those to New York and Paris, we can say the journey to New York takes the greatest amount of time.

Want to test your skills in comparing durations of time? Have a go at this quiz!