Goal: I want to subtract lunch time if I work over 5 hours, otherwise I
want
to know the hours worked if under 5 hours)

Details:

Cell A10 - lunch time, cell is number format, time
Cell E10 - time I arrived at work, custom cell format h:mm AM/PM
Cell F10 - time I leave work, custom cell format h:mm AM/PM
Cell B10 - is cell to enter the formula and then convert it to decimal

=If(F10-E10 is greater than 5 hours, then F1-E10-A10, else, F10-E10)*24
(it is mandatory to take lunch if you work 5 hours or more)

Can anyone provide the correct formula and/or cell formats?

My problem is that I don't know how to recognize the 5 hours in the formula.