Year 4 - Maths
Convert between times given in 12 and 24 hours
Time: Convert between 12 and 24 hour clocks: analogue and digital
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
In this unit pupils will read, write and convert time between analogue and digital 12- and 24-hour clocks. They will solve problems involving converting from hours to minutes, minutes to seconds, years to months, weeks to days.
Lesson Summary
You will learn to convert between times given in 12 and 24 hours.
Key Notes
- There are 24 hours in a day
- Times after midday can be written as pm
- Times after midday can be written in the 24 hour clock by adding on 12 hours
Vocabulary To Learn
- am: The hours between midnight and midday.
- pm: The hours between midday and midnight.
- 24 hour clock: A way of expressing the time using the numbers 0-23 for the hours.
Common Mistakes To Avoid
- It is tempting to say that we need to add 12 hours to any pm times to turn them into 24 hour times. However, it is a slight over-generalisation and does not apply to 12:00 pm up to 12:59 pm.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
There are 24 hours in a day. Times after midday can be written as pm.
2. Use this key word in a maths sentence and explain it clearly. 'am'
The hours between midnight and midday. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: It is tempting to say that we need to add 12 hours to any pm times to turn them into 24 hour times. However, it is a slight over-generalisation and does not apply to 12:00 pm up to 12:59 pm. Correction: A teaching point is made of this and opportunities to apply the knowledge are given in the Practice tasks. It is worth really focusing on this as it comes up and paying attention to it while pupils are engaged with the Practice tasks.
More Lessons In This Unit
Browse all guides in the Year 4 Maths guide library.