Sixty seconds make a minute
A second is a very short time. A blink of your eye takes about one second. Seconds measure quick things, and 60 seconds make 1 minute.
Second is shortened to s, and minute to min, so 1 minute = 60 seconds is written 1 min = 60 s. It works like the hour: 60 minutes make an hour, and 60 seconds make a minute.
Counting seconds in fives: 5, 10, 15, and on to 60. The 60 seconds make one minute.
Minutes and seconds together
Each minute holds 60 seconds, so 3 min = 60 + 60 + 60 = 180 s. A time like 1 min 15 s is one minute and 15 seconds more: 60 + 15 = 75 s.
To go the other way, take out groups of 60 seconds. 75 s is 60 s and 15 s more, so 75 s = 1 min 15 s. The seconds part is always less than 60, because 60 more seconds would make another minute.
One minute is 60 seconds, and 15 seconds more reach 75: 1 min 15 s = 75 s.
Choosing the unit
Seconds are used for quick things: a blink takes about 1 s, and tying a shoe takes about 30 s. Minutes are used for longer things: a song lasts about 3 min, and brushing your teeth takes about 2 min. Hours are used for longer things still, like a school day of about 6 h.
To estimate how long something takes, choose the unit that gives a sensible number. A song lasts about 3 min. It does not last 3 s, which is about three blinks, or 3 h, which is longer than most films.
Three minutes in seconds. Tying a shoe takes 30 s, and a song lasts about 180 s, which is 3 min. A blink, 1 s, is too short to see on this line.
Worked example: Two Race Times, One in Minutes and Seconds
Question Ali and Ben each swim one lap of the pool. Ali takes 2 min 15 s. Ben takes 128 s. (a) What is Ali's time in seconds? (b) Who is faster, and by how many seconds?
1.1 minute is 60 seconds, so 2 minutes are 60 + 60 = 120 seconds.
1 minute is 60 seconds, so 2 minutes are 60 + 60 = 120 seconds. 2.(a) Add the 15 seconds: 120 + 15 = 135. Ali's time is 135 seconds.
(a) 120 + 15 = 135 seconds. 3.Now both times are in seconds. Ali took 135 s and Ben took 128 s. The faster swimmer takes less time, and 128 is less than 135.
Both times are in seconds now, and 128 is less than 135. 4.(b) Ben is faster, by 135 − 128 = 7 seconds.
(b) Ben is faster, by 135 − 128 = 7 seconds.
Answer: (a) 135 seconds; (b) Ben, by 7 seconds
Common mistakes
- Writing 2 min 15 s as 215 seconds. The 2 stands for 2 minutes, and each minute is 60 seconds, so the time is 120 + 15 = 135 seconds.
- Saying that Ali is faster because 135 is the bigger number. In a race the faster swimmer has the smaller time.
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