You can do math on dates and times exactly as you would with numbers.

a b c d
09:00 12:00 13:00 17:00

=(b1-a1)+(d1-c1)


"Calculation of hours worked." wrote:

I am fairly new to Excel, but I need the formula to calculate hours worked,
to include 30-60 min off for lunch. Formula must include hours and minutes
worked.