Time Calculation For A Timesheet To Include Lunch

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

Assume cell A1 has time in, B1 has time out, and C1 has the number of
hours (not minutes) for lunch. The formula would be:

=HOUR(B1)-HOUR(A1)-C1

If you want to track lunch in hours and minutes, I think there's a
minute function out there (did not test).

HTH,
Johnny

Thanks very much for your help - it looks as if many helpful people are
already responding to my request - Thanks to you all....

I did FINALLY manage to solve the problem as follows:

=D4-C4-TIME(0,E4*60,0)

C4 is my Start Time, D4 is my End Time, and E4 is the Lunch Time. I
tried to deduct this as hours which was ok for whole hours, so I
changed my TIME formula to multiply the Lunch by 60 (ie: 1.00 is 60
minutes, 0.50 is 30 minutes) and that worked.

Such a simple task has to be so complicated....
Thanks again everyone.