Primary 3 Time Study Guide
Primary 3 time in five short steps: why time counts in sixties, then seconds, the 24-hour clock, timelines for durations, and journeys with breaks, with something to try at each step and worked examples to finish.
Start here
How do you work out a duration in P3?
Jump to the next hour first, then jump the rest.
Time counts in sixties, not hundreds: 60 seconds make 1 minute and 60 minutes make 1 hour. So 08 50 plus 25 minutes is not "08 75". Jump 10 minutes to 09 00, then the 15 minutes still to go: 09 15.
In this chapter, your child uses this to:
- change seconds to minutes by finding how many 60s fit;
- read the 24-hour clock, where the hours keep counting past 12;
- find a starting time, finishing time or duration with jumps on a timeline;
- add the stages of a journey, and leave out a break when the question asks.
Step 1
Seconds, minutes and hours
Every 60 seconds make a minute. The seconds hand goes once round the stopwatch in 60 seconds. To change seconds into minutes and seconds, count the full laps of 60, then the seconds left over.
Drag the slider, or start the stopwatch
A song lasts 4 min 15 s. How many seconds is that?
Step 2
The 12-hour and 24-hour clocks
After noon, the hours keep counting. The 24-hour clock starts at 00 00 at midnight and counts all the way to 23 59. From 1 pm, add 12 to the hour. Write four digits with a space, with no colon and no am or pm
Drag the long hand round, or use the buttons
The outer ring shows the 24-hour hour.
Write 9:05 pm using the 24-hour clock.
Step 3
Starting time, finishing time and duration
Two of them give you the third. Mark what you know on a timeline. Jump forwards to find a finishing time, and backwards to find a starting time. For a duration, jump from the start to the finish and add up the jumps.
A puppet show starts at 14 40 and lasts 45 min. At what time does it finish?
Step 4
Journeys, breaks and fast or slow clocks
Fix the clock, then count, then leave out the break. A fast clock is ahead, so count back. A slow clock is behind, so count on. A duration includes any break; the time spent on the activity does not.
Kavin leaves at 08 40 and rests for 15 min on the way. When he arrives, the estate clock shows 10 05, but it is 5 min fast. How long was he riding?
The school hall clock is 8 min fast. It shows 07 50. What is the actual time?
Primary 3 time questions, worked step by stepTry each question first. Then show a hint, or the working one line at a time.
Mei Ling held a plank for 3 min 25 s. Siti held it for 190 s. Who held the plank longer, and by how many seconds?
- 3 min = 3 × 60 = 180 s
- Mei Ling: 180 s + 25 s = 205 s
- 205 s is more than 190 s, so Mei Ling held it longer.
- Difference = 205 − 190 = 15 s
A night train leaves at 10:45 pm The journey takes 1 h 30 min.
(a) Write the leaving time using the 24-hour clock.
(b) At what time does the train arrive? Use the 24-hour clock.
- (a) 10:45 pm is after noon: 10 + 12 = 22, so 22 45
- (b) 22 45 + 1 h = 23 45
- 23 45 + 15 min = 00 00, midnight. Minutes still to add = 30 − 15 = 15 min
- 00 00 + 15 min = 00 15 the next day
A concert ended at 16 10. It lasted 2 h 25 min. At what time did the concert start? Use the 24-hour clock.
- 16 10 − 2 h = 14 10
- Jump back 10 min: 14 10 − 10 min = 14 00
- Minutes still to go back = 25 − 10 = 15 min
- Starting time = 14 00 − 15 min = 13 45
A school fun fair opened at 10 35 and closed at 15 20 on the same day. How long was the fun fair open? Give your answer in hours and minutes.
- 10 35 to 11 00: 60 − 35 = 25 min
- 11 00 to 15 00: 4 h
- 15 00 to 15 20: 20 min
- Minutes together = 25 + 20 = 45 min
- Duration = 4 h 45 min
Bala started his homework when the kitchen clock showed 19 25. The kitchen clock is 10 min slow. He took one break of 15 min, and finished at 21 05 by his watch, which shows the correct time. How long did Bala spend on his homework, not counting the break?
- Actual starting time = 19 25 + 10 min = 19 35
- 19 35 to 20 00: 25 min. 20 00 to 21 00: 1 h. 21 00 to 21 05: 5 min
- Whole time = 25 min + 60 min + 5 min = 90 min
- Homework time = 90 min − 15 min = 75 min
- 75 min = 60 min + 15 min = 1 h 15 min
Step 5
Check yourself
Five quick questions from across the chapter. Answers are not saved; they show where to practise next.
1. Add 2 min 50 s and 35 s. Give your answer in minutes and seconds.
2. Write 00 25 using the 12-hour clock.
3. How long is it from 09 35 to 11 10 on the same day?
4. A film ends at 21 15. It lasts 1 h 50 min. At what time does it start?
5. Nurul's swimming session ran from 15 30 to 17 00, with a 20 min break in the middle. How long did she spend swimming?
How to use this guide. Sit with your child for the clock in Step 2. Before they drag the hand, ask "What will the 24-hour clock say after 1 pm?" Saying it aloud is half of the learning. Each step takes two or three minutes; the whole guide about fifteen.
At home, a microwave or an oven timer is a good prompt: ask how many seconds 1:30 on the display is. On an outing, ask your child to find how long the bus ride took by jumping to the next hour first. The worked examples show how these ideas are used in test questions; let your child try first, then reveal one line at a time.
More study guides
P3 Time lessons and practice
4 lesson videos and 39 questions across four subtopics, from Basic to Challenge, each with a worked solution.
Watch and practise →