### 24 Hour Party Notes

In the run up to my son's tests this November, I've been trying to identify some of the areas that he often makes mistakes in and do him little revision notes on post-its for his room. Here's the first on the 24-hour clock.

The trickey bit of the 24-hour clock is counting through midnight (00:00). A mistake that I have seen a few times is that he counts up over 23:59 and tries to go to 24:00.

### The 24-hour clock never reads 24:00!

Another common mistake that I have seen in his work (and in others) is about the adding of 12 hours to a 12-hour clock time when it's pm.

Example 1: Convert 3:25pm to 24-hour format.

Answer 1:  3:25 + 12:00 = 15:25 .

OK - that seem to work. If it's pm we add 12 hours, correct? Well, not always...

Example 2: Convert 12:25pm to 24-hour format.

In the second example the rule doesn't work. Ask your child how they convert and talk through this exception with them.

### To convert 12hr to 24hr format, add 12 hours between 1pm and 11:59pm

Lastly, when you are counting back over midnight to find the length of a movie or a flight or whatever, do it in steps and jot these down. DO NOT do these in your head - it's hard for you to check at the end.