Problem Area: Elapsed Time

This seems to be a problem area for a lot of our students this year. Please practice with your notes and old problems. Here is an example:

Kelly leaves home at 9:14 am to go shopping. She gets back home at 1:35 pm. How long was Kelly gone?

First, figure out the whole hours by writing:
Start 9:14 am
10:14am
11:14 am
12:14 pm
1:14 pm
How many hours is that? Do not count the starting time. You should have gotten 4 hours.

Now figure out how many minutes it is between 1:14pm and 1:35pm. You will want to "chunk" the minutes in little bits that you are comfortable working with. Here's one way you can do it:

1:14-1:24 = 10 minutes
1:24-1:34 = 10 minutes
1:34-1:35 = 1 minute
Now add all of the minutes and you get 21 minutes, so your final answer would be:

4 hours and 21 minutes