The idea, step by step
Choose a unit that fits
Seconds suit a short clap, minutes suit a short game, hours suit a school day and days suit a holiday.
Time units do not always change in groups of ten. There are 60 seconds in a minute and 60 minutes in an hour.
Join equal time groups
Two minutes means two groups of 60 seconds: 120 seconds. Add extra minutes separately when a time includes hours and minutes.
A whole day has 24 hours. Keep the unit in the answer so that 24 hours is not confused with 24 minutes.
| Unit | Equal amount |
|---|---|
| 1 minute | 60 seconds |
| 1 hour | 60 minutes |
| 1 day | 24 hours |
A common trap
Changing an hour into 100 minutes.
Instead: Use the time relationship: 60 minutes make an hour.
See the thinking
Skipping time
How many seconds are in 2 minutes?
- Each minute is 60 seconds.
- 60 + 60 = 120.
A journey
A trip lasts 1 hour 20 minutes. How many minutes is this?
- Change 1 hour into 60 minutes.
- 60 + 20 = 80.
Check your understanding
Which unit best describes a blink: seconds, hours or days?
Show answer
Seconds
A blink is very short.
Your turn
6 questions · Work at your own pace.
Read the questions online
- How many seconds are in 1 minute?
- How many minutes are in 2 hours?
- How many hours are in 1 day?
- Choose seconds or days for measuring a four-week school holiday.
- Change 1 hour 15 minutes into minutes.
- Mia says 90 seconds is longer than 2 minutes. Is she right? Explain.
Read the worked solutions
- How many seconds are in 1 minute?
Use 1 minute = 60 seconds.
60 seconds - How many minutes are in 2 hours?
60 + 60 = 120.
120 minutes - How many hours are in 1 day?
A whole day has 24 hours.
24 hours - Choose seconds or days for measuring a four-week school holiday.
A holiday lasts many whole days.
Days - Change 1 hour 15 minutes into minutes.
60 + 15 = 75.
75 minutes - Mia says 90 seconds is longer than 2 minutes. Is she right? Explain.
Compare both times in seconds.
120 is greater than 90.
No. Two minutes is 120 seconds, so 90 seconds is shorter.
Curriculum reference & lesson scope
Australian Curriculum v9 and SA Curriculum
Analogue/digital clocks to the minute; seconds/minutes/hours/days; duration.
Official curriculum source ↗