Timesheet differences

Need to look a the codes in column a and the employee id in column b and if the
Code 1 = hours worked (total to be 80) so this one needs to change in other words it should equeal code 7 + code 4 - 80 = gives hours worked I just can't figure out how to put it togeather thanks
Code 4 = pto time
Code 7 = Holiday which is 8.
how can I get it to look at all and give me a total thanks
I have included the file