Time

Maths: Edexcel IGCSE Higher, topic 4.4.2

The 12-Hour Clock

The minute hand shows the exact minute past the hour.

Sections of a clock

Each number represents a different number of minutes.
The number of minutes between each number on the clock is 5 minutes.

Example

This clock shows the time as 10 past 3. This is because:
The minute hand has passed two five minute sections since passing o'clock (at 12).
The last number the hour hand passed was 3.

Example 2

This clock shows the time as 10 to 8. This is because:
The minute hand has two more five minute sections until it reaches o'clock (at 12).
The next number the hour hand passes will be 8.

24-Hour Clock

The 24-hour clock doesn't use am or pm. Instead, it gives the hour of the day starting from 0 at the start of the day and running up to 24 at the end of the day. 12 is at midday.

In the morning (am)

Times before midday are the same in a 24-hour or 12-hour format. The only difference is you don't need the "am" when using the 24-hour clock.
E.g. 10:40 am is 10:40 in the 24-hour clock.
E.g. 09:20 am is 09:20 in the 24-hour clock.

Midday

Midday is the same in the 24-hour and 12-hour clock with the "pm" removed.
Midday in the 12-hour clock is 12:00 pm or 12:00 noon.
Midday in the 24-hour clock is 12:00.

In the afternoon (pm)

1 o'clock in the afternoon is 1:00 pm in the 12-hour clock.
1 o'clock in the afternoon is 13:00 in the 24-hour clock.
This is because the 24-hour clock carries on counting from 12 noon.

Examples

6 o'clock in the afternoon is 18:00 in the 24-hour clock.
4 o'clock in the morning is 04:00 in the 24-hour clock.
12 midnight is 00:00 in the 24-hour clock.
10 o'clock in the evening is 22:00 in the 24-hour clock.

Uses of the 24-hour clock

The 24-hour clock is often used on timetables.
E.g. bus, train and plane timetables
You'll also normally see the time on your phone in a 24-hour clock.

Reading Timetables

You can use timetables to work out differences in time and when certain events will start. You need to be familiar with the 24-hour and 12-hour clock for this topic

Timetables

Train/bus timetables have locations in the first column.
Each column after that shows the running of a single train/bus.
The time shown shows the time that train/bus leaves from each location.
The first location is displayed at the top of the table and the last location is at the bottom.

Example

The first train left Derby ar 11:25, got to Sheffield at 12:06, Wakefield Westgate at 12:36, Leeds at 12:54, York at 13:31 and Darlington at 14:02.
The second train left Derby ar 11:55, got to Sheffield at 12:56, Wakefield Westgate at 13:06, Leeds at 13:24, etc.

Example 2

The dashes (−) mean that the train did not stop at that location.

Calculations

You can use the timetable to work out the journey times between different locations.
E.g. the journey time from Wakefield Westgate to Leeds is the difference between 12:36 and 12:54. The difference in this example is 18 minutes.

Example

The journey time from Sheffield to Leeds when the train makes a stop at Wakefield Westgate is the difference between 12:06 and 12:54. The difference in this example is 48 minutes.
The journey time from Sheffield to Leeds when the train doesn't a stop at Wakefield Westgate is the difference between 13:06 and 13:49. The difference in this example is 43 minutes.

Test yourself on Time

What time does this clock show?
What time does this clock show?
What time does this clock show?
What time does this clock show?
What time does this clock show?

Practise this topic for free