Seconds, the 24-hour clock and timetables · Usually met around P3
Seconds
1 min = 60 s; fewer seconds is faster.
How to do it
Method
1 min = 60 s; fewer seconds is faster
1 min 20 s = 60 + 20 = 80 s
Another way
Count in fives
5, 10, 15, 20 …
In full
A second (s) is shorter than a minute: the second hand moves one small step a second and goes once round in 60 seconds, so 1 minute = 60 seconds. Very short times — a clap, a 50 m run — are measured in seconds. In a race, the fewer seconds, the faster. To change minutes to seconds, multiply by 60 and add the seconds: 1 min 20 s = 60 + 20 = 80 s. Or count on a stopwatch in fives from 0: 5, 10, 15…
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
Ka-yee runs 50 m in about 9 □. Which unit goes in □?
- A. days
- B. minutes
- C. hours
- D. seconds
Choose the right answer
Show the answer and working
Answer: D. seconds
A 50 m run takes a very short time, so use seconds: about 9 s.
Example 2
1 min 44 s = □ s
Show the answer and working
Answer: 104
1 minute is 60 seconds: 60 + 44 = 104.
Example 3
Tsz-ching runs 100 m in 18 s and May in 14 s. How many fewer seconds did the faster one take?
Show the answer and working
Answer: 4 s
Bigger take away smaller: 4 s.
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