I have seen many postings for time calculation but nothing that
includes a factor for lunch.
I am trying to create a Timesheet so I can calculate the number of
hours worked per day, but have not been able to find a way to include
the Lunch time in the formula and to have it displayed correctly.

I have cells for Start Time and End Time formatted as HH:MM, plus Lunch
formatted as Numeric. Example: Start 8:30AM, End 5:30PM, Lunch 1:00

A formula of End - Start (ie: D4-C4) will give me 9:00 (9 hours).
How can I deduct the 1 hour for lunch?
This is not a time, just a number of hours/minutes.
I tried converting to all different values with no luck.
Thanks in advance.
Tony