# 6.02 24 hr time

Lesson

## Are you ready?

How many hours are displayed on a clock? How many hours are in a day?

Idea summary

12 hours are displayed on a clock, but there are 24 hours in a day.

Since 12 goes into 24 \, \, 2 times, the hour hand will go around a clock 2 times in a day.

## 12 and 24 hour time

This video explores how a 24 hour clock works and demonstrates how to switch between 12 and 24 hour time.

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### Examples

#### Example 1

Convert 3\text{:}41 pm into 24-hour time.

Worked Solution
Create a strategy

Add 12 hours to 12-hour pm time to convert to 24-hour time.

Apply the idea

Add 12 to 3 pm:3+12=15

So the 24-hour time is:15\text{:}41

Idea summary

To convert 12-hour pm time to 24-hour time, we add 12 to the number of hours.

We don't express midnight as 24\text{:}00 using the 24 hour clock, instead, we write 00\text{:}00 as it's the start of the day. When using the 12 hour clock, we write midnight as 12\text{:}00 AM.

### Outcomes

#### VCMMG197

Compare 12 and 24 hour time systems and convert between them.