Time calculations, unit conversions, speed-distance-time.
CoreIn almost every paper that tests this subjectAbout 60 seconds a question in the test
The big idea
Remember the metric conversions: 10 mm = 1 cm, 100 cm = 1 m, 1000 m = 1 km, 1000 g = 1 kg, 1000 ml = 1 l.
For time, count on in steps to the next hour. Speed = distance ÷ time, so distance = speed × time.
Tips that save marks
Never use a calculator-style subtraction for times. There are 60 minutes in an hour, not 100.
Convert to the same units before calculating.
Use a number line to work out durations.
A worked example
A train leaves at 09:47 and arrives at 11:15. How long is the journey?
09:47 → 10:00 is 13 min.
10:00 → 11:15 is 1 h 15 min.
Total: 1 h 28 min.
Now try five
Try each one before you look at the answer: answering from memory is what makes it stick. Tap an option to check it. Most children get three or four right at first; five out of five means move on to the next topic.
Question 1Aim for about 60 seconds
How many minutes does Bus 4 take to go from the Station to the Library?
Bus 1
Bus 2
Bus 3
Bus 4
Station
08:10
08:36
09:06
09:40
Market
08:18
08:44
09:14
09:48
Library
08:31
08:57
09:27
10:01
Park
08:39
09:05
09:35
10:09
Show the worked answer
Answer: C, 21 minutes
How to work it out
Bus 4 leaves the Station at 09:40 and reaches the Library at 10:01.
Count on: 21 minutes.
Why the other options are wrong
A (8 minutes): This is only the first part of the journey.
B (61 minutes): This subtracts the times as if there were 100 minutes in an hour.
D (31 minutes): Count on again from the departure time.
E (−69 minutes): This reads the arrival time from the wrong bus.
Question 2Aim for about 60 seconds
How many minutes does Bus 4 take to go from the Station to the Park?
Bus 1
Bus 2
Bus 3
Bus 4
Station
08:10
08:39
09:00
09:34
Market
08:16
08:45
09:06
09:40
Library
08:26
08:55
09:16
09:50
Park
08:31
09:00
09:21
09:55
Show the worked answer
Answer: C, 21 minutes
How to work it out
Bus 4 leaves the Station at 09:34 and reaches the Park at 09:55.
Count on: 21 minutes.
Why the other options are wrong
A (−63 minutes): This reads the arrival time from the wrong bus.
B (5 minutes): This is only the last part of the journey.
D (31 minutes): Count on again from the departure time.
E (6 minutes): This is only the first part of the journey.
Question 3Aim for about 60 seconds
Kiran must be at the Library by 09:10. What is the latest bus Kiran can catch from the Station?
Bus 1
Bus 2
Bus 3
Bus 4
Station
08:10
08:36
09:20
09:25
Market
08:23
08:49
09:33
09:38
Library
08:36
09:02
09:46
09:51
Park
08:47
09:13
09:57
10:02
Show the worked answer
Answer: D, 08:36
How to work it out
Look along the Library row for the last time at or before 09:10: 09:02, which is Bus 2.
That bus leaves the Station at 08:36.
Why the other options are wrong
A (08:10): This bus works, but a later one also arrives in time.
B (09:02): This is when the bus reaches the Library, not when it leaves the Station.
C (09:20): That bus reaches the Library at 09:46, which is too late.
E (08:44): Buses only leave at the times in the timetable.
Question 4Aim for about 60 seconds
If 28 December is a Friday, what day of the week is 16 February?
Show the worked answer
Answer: C, Saturday
How to work it out
Count the days: 3 more in December, 31 in January and 16 in February, so 50 days.
50 = 7 weeks and 1 day.
Whole weeks bring you back to Friday; 1 more day gives Saturday.
Why the other options are wrong
A (Thursday): This treats December or January as having 30 days; both have 31.
B (Friday): This counts one day too few. Count the days after the start date, up to and including the end date.
D (Monday): Check the number of days left in December again.
E (Sunday): This counts one day too many: the start day itself is not counted.
Question 5Aim for about 60 seconds
A car travels at 70 mph for 2.5 hours. How far does it travel?
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