I'm trying to calculate length of hours with a break included, but I'm not
sure it's calculating correctly. Here's what I have in military time:

C6=8:00
C7=12:30
C8=13:30
C9=17:25

The formula I have to calculate the total of those hours is:
=C9-C6-1/24+(C9C6)

The break is usually 1 hour, but it can be less or more than 1 hour so I'd
like to change my formula if possible to allow for that variation.

I'm also trying to add the total hours together, but it's not displaying
right. My hours a

8:25 + 8:15 + 8:15 + 8:25 + 8:00 = 6.72

I used the sum function, but I know all that adds up to more than 6.72. :-)

TIA!
Anita