The idea, step by step
Use the correct groups
One minute contains 60 seconds. One hour contains 60 minutes. One day contains 24 hours. Time units are not all groups of ten, so do not move decimal digits as if every unit behaved like centimetres and millimetres.
| Unit | Equal duration |
|---|---|
| 1 minute | 60 seconds |
| 1 hour | 60 minutes |
| 1 day | 24 hours |
Keep the remainder
To write 95 minutes using hours and minutes, make one group of 60 minutes. There are 35 minutes left. Therefore 95 minutes is 1 hour 35 minutes. The leftover minutes must be less than 60. Group seconds into minutes in the same way.
A common trap
Writing 90 minutes as 1 hour 90 minutes.
Instead: The first 60 minutes have already been used. Only 30 minutes remain.
See the thinking
Three hours
How many minutes are in 3 hours?
- Each hour contains 60 minutes.
- 3 groups of 60 give 180.
A mixed duration
Write 150 seconds using minutes and seconds.
- Two groups of 60 make 120 seconds.
- 150 − 120 = 30 seconds remain.
Check your understanding
How many minutes are in 2 hours 15 minutes?
Show answer
135 minutes.
120 + 15 = 135.
Your turn
6 questions · 7 marks · Work at your own pace.
Read the questions online
- Convert 4 minutes to seconds.1 mark
- Convert 2 hours to minutes.1 mark
- Convert 1 hour 20 minutes to minutes.1 mark
- Write 125 minutes as hours and minutes.1 mark
- Convert 2 days to hours.1 mark
- Luca says 3 minutes 20 seconds is 320 seconds. Correct his answer.2 marks
Read the worked solutions
Equivalent correct methods earn the corresponding marks. Include units where asked.
- Convert 4 minutes to seconds.1 mark
4 × 60 = 240.
240 seconds. - Convert 2 hours to minutes.1 mark
2 × 60 = 120.
120 minutes. - Convert 1 hour 20 minutes to minutes.1 mark
60 + 20 = 80.
80 minutes. - Write 125 minutes as hours and minutes.1 mark
120 minutes makes 2 hours, leaving 5 minutes.
2 hours 5 minutes. - Convert 2 days to hours.1 mark
2 × 24 = 48.
48 hours. - Luca says 3 minutes 20 seconds is 320 seconds. Correct his answer.2 marks
3 minutes is 180 seconds.
180 + 20 = 200 seconds; time units are not groups of 100.
200 seconds.
Curriculum reference & lesson scope
Australian Curriculum v9 / SA Curriculum Mathematics 2026
am/pm; unit conversions; start/finish/elapsed time.
Official curriculum source ↗