Chapter 13.4 (Mathematics 5)

Arithmethic with Time. Subtraction

Subtraction of minutes and seconds

Group Activity 6

In groups of five:

  1. Take two different time periods, each in minutes and seconds.
  2. Subtract the smaller time from the larger time.
  3. Discuss and share your method with other groups.

Example 4a

Work out 29 minutes 36 seconds – 14 minutes 23 seconds.

minutes seconds 29 36 - 14 23 15 13

Example 4b

Work out 40 minutes 15 seconds – 18 minutes 27 seconds.

minutes seconds 40 15 - 18 27 21 48 or

minutes seconds 39 75 - 18 27 21 48

  1. 15 – 27 is not possible.
  2. Regroup 1 minutes from 40 to 60 seconds.
  3. Convert 1 minutes to 60 seconds
    ​Add 15 to 60 to get 75 seconds.
  4. 75 – 27 = 48. Write 48 in the seconds column.
  5. 39 – 18 = 21. Write 21 in the minutes column

Note

1 minute = 60 second

40 minutes = 39 minutes + 60 seconds

Exercise F

a) minutes seconds 15 25 - 17 19

b) minutes seconds 29 53 - 15 20

c) minutes seconds 37 45 - 18 25

a) minutes seconds 35 40 - 35 50

b) minutes seconds 25 13 - 10 15

c) minutes seconds 42 26 - 47 38

  1. 31 minutes 24 seconds – 25 minutes 12 seconds =
    =  minutes  minutes
  2. 44 minutes 35 seconds – 12 minutes 20 seconds =
    =  minutes  seconds
  3. 41 minutes 36 seconds – 29 minutes 48 seconds =
    =  minutes  seconds
  4. 55 minutes 7 seconds – 43 minutes 46 seconds =
    =  minutes  seconds

Answer. The difference is  minutes  seconds.

Answer. The difference is  minutes  seconds.