Simple decimal time question for any of you Excel fanatics out here 
I have a client who enters times onto a timesheet in the format of:
0.5
-3.5
1
-1.5
3
0.75
4
(where the minus figures represent time owed/overtime).
When this is totalled, it comes to 4.25 (4h 15m) however the actual figure should be 3h 55m.
I confirmed that by changing the figures to times (e.g 0.75 = 00:45:00 etc)
Can i have this so that she can carry on entering times as decimals, but have the correct total displaying?!
Apologies if I’m doing something dumb!
Thanks!

I have a client who enters times onto a timesheet in the format of:
0.5
-3.5
1
-1.5
3
0.75
4
(where the minus figures represent time owed/overtime).
When this is totalled, it comes to 4.25 (4h 15m) however the actual figure should be 3h 55m.
I confirmed that by changing the figures to times (e.g 0.75 = 00:45:00 etc)
Can i have this so that she can carry on entering times as decimals, but have the correct total displaying?!
Apologies if I’m doing something dumb!
Thanks!