Chapter 13.2 (Mathematics 5)

Conversion of units of time

Conversion of minutes to seconds

Group Activity 3

In groups of five:

  1. Multiply any 2-digit number by 60.
  2. Use the same method to multiply a number by 60 seconds.
  3. Discuss the conversion of minutes to seconds and share your method with other groups.

Example 1a

Convert 5 minutes to seconds.

  1. 1 minute = 60 seconds
  2. 5 minutes = 5 × 60 seconds = 300 seconds

Example 1b

Convert 3 minutes and 20 seconds to seconds.

  1. 1 minute = 60 seconds
  2. 3 minutes = 360 seconds = 180 seconds
  3. 3 minutes 20 seconds =
    =​ 180 seconds + 20 seconds =
    =​ 200 seconds

Exercise C

  1. 7 minutes =  seconds
  2. 11 minutes =  seconds
  3. 20 minutes =  seconds
  4. 32 minutes =  seconds

a) 1 min 10 seconds =

 seconds

b) 3 minute 54 seconds =

 seconds

c) 7 min 45 seconds =

 seconds

d) 3 minutes 53 seconds =

 seconds

Answer. The race took  seconds.

Answer. She took  seconds to prepare the meal.

Answer. He took  seconds to read the chapter.

Conversion of seconds to minutes

In groups of five:

  1. Take a 3-digit number, for example, 245.
  2. Divide the number by 60.

    60 - 245 -    

  1. Use the same method to divide 750 seconds by 60.
  2. Discuss and share your results with other groups

  60 - 750 -    

Example 2a

Convert 540 seconds to minutes.

  1. 60 seconds = 1 minute
  2. 540 seconds = 540 ÷ 60 seconds
    9  60 540 -540  0   
  3. 540 seconds = 9 minutes

Example 2b

Convert 130 seconds to minutes and seconds.

  1. 60 seconds = 1 minutes
  2. 130 seconds = 130 ÷ 60 seconds
    2  60 130 -120  10  ​
  3. 130 seconds = 2 minutes 10 seconds

Exercise D

  1. 180 seconds =  minutes
  2. 240 seconds =  minutes
  3. 420 seconds =  minutes
  4. 600 seconds =  minutes

a) 150 seconds =

 min  s

b) 190 seconds =

 min  s

c) 580 seconds =

 min  s

d) 650 seconds =

 min  s

Answer. The time was  minutes  seconds.

Answer. The time was  minutes  seconds.

Answer. The time was  minutes  seconds.

Digital Time

Conversion of seconds to minutes and seconds