Calculating time intervals - time lines
There are different methods for calculating time intervals.
It doesn't matter which one you choose, as long as you feel confident about using it.
However, whichever way you decide, show some working. It helps your time answers to be clear.
Example
Daniel starts school at 8.25am and finishes at 3.15pm. How long does his school day last?
This can be calculated two ways, using Time Lines and Counting On.
Time lines
This is where the time interval is shown on a time line.
Step One
First draw a line with 8.25am (when Daniel started school) at one end and 3.15pm (when Daniel finished school) at the other.
Step Two
Next mark 9am and 3pm on the line.
If you want to, mark in 12 noon.
Step Three
Now calculate the time interval for each section.
Step Four
Add them up.
\(3hrs + 3hrs + 35mins + 15mins = 6hrs 50mins\)
