Calculating time to track work hours

I can't figure out how to do a proper formula for calculating time. For instance I have one column that says "Time In", the next is "Time Out" and the other is "Lunch Time". My calculation needs to be this:

Find the total hours between the Time In and Time Out and then Minus the lunch time to get total hours worked for the day.

The only way I can get this to work is using 24 Hour time format. Is there another way?

The typical way to calculate hours worked with a break would be to have four cells, for example:
A1 = Time In (beginning of day)
A2 = Time Out for Lunch
A3 = Time In from Lunch
A4 = Time Out (end of day)

You would then use the formula:

=(A2-A1)+(A4-A3)

Hope that helps!

No need to use 24 hour time as long as you're entering your in/out times as AM and PM.

In: 7:00 AM
Out: 12:00 PM
In: 1:00 PM
Out: 5:00 PM