Key ideas
Time intervals
Count on: to the next hour, then whole hours, then the minutes left.
09:45 → 10:00 → 13:00 → 13:20 = 3 h 35 min
Time zones
Places to the east of the UK are ahead: add the hours.
Places to the west are behind: take away the hours.
Flights
1. Add the flight time to the departure time.
2. Then change it into the local time where you land.
Watch out for going past midnight: that is the next day.
Finding a flight time
Change both times into the same time zone first.
Then find the time interval.
| Place | Time compared with the UK (winter) |
|---|---|
| Los Angeles | 8 hours behind |
| New York | 5 hours behind |
| UK (London) | same as UK |
| Paris | 1 hour ahead |
| Dubai | 4 hours ahead |
| Beijing | 8 hours ahead |
| Tokyo | 9 hours ahead |
| Sydney | 11 hours ahead |
Time intervals
A train leaves at 09:45 and arrives at 13:20. How long is the journey?(2 marks)
Count on.15 min + 3 h + 20 min✓1
In plain EnglishCount on to the next hour (15 minutes), then whole hours to 13:00 (3 hours), then the minutes left (20 minutes).
Add them up.= 3 h 35 min✓2
In plain EnglishAdd the pieces: 3 hours, plus 15 min + 20 min = 35 min.
Time in other countries
It is 14:00 in the UK. What time is it in (a) Tokyo (b) New York?(2 marks)
Tokyo is 9 hours ahead.14:00 + 9 h = 23:00✓1
In plain EnglishTokyo is east of the UK, so its clocks are ahead. Add 9 hours.
New York is 5 hours behind.14:00 − 5 h = 09:00✓2
In plain EnglishNew York is west of the UK, so its clocks are behind. Take away 5 hours.
It is 20:30 on Monday in the UK. What time and day is it in Sydney?(1 mark)
Count on 11 hours.20:30 → midnight = 3 h 30 min11 h − 3 h 30 min = 7 h 30 min more07:30 on Tuesday✓1
In plain EnglishCount on to midnight first. The rest of the 11 hours carries on into the next day.
Arriving in another time zone
A flight leaves London at 10:30 (UK time). It takes 7 hours 45 minutes to fly to New York. What is the local time in New York when it lands?(3 marks)
Add the flight time.10:30 + 7 h 45 min = 18:15 UK time✓1
In plain EnglishFirst work out the time it lands, using UK time: 10:30 + 7 h = 17:30, + 45 min = 18:15.
Change to New York time.New York is 5 hours behind✓218:15 − 5 h = 13:15 New York time✓3
In plain EnglishThe passengers set their watches back 5 hours.
⚠ A common mistake: stopping at 18:15. That is the time in the UK, not in New York.
Finding the flight time
A flight leaves Dubai at 08:15 local time and lands in London at 12:40 UK time. How long is the flight?(3 marks)
Change to the same time zone.Dubai is 4 hours ahead of the UK08:15 Dubai = 04:15 UK time✓1
In plain EnglishThe two times are in different zones, so change the departure time into UK time first.
Find the interval.45 min + 7 h + 40 min✓2= 8 h 25 min✓3
In plain EnglishNow count on from 04:15 to 12:40.
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Your turn
Give clock times in the 24-hour clock, with hours and minutes in separate boxes (for 07:30 type 7 and 30). Use the time zone table in each question. Stuck? Tap Need a hint?