How do I get the sum in hours and minutes for a range of fields that
are formatted as "time" (hh:mm)?

I have two columns, one with starting time, one with ending time and a
third column that calculates the difference between ending and
starting time.
I can sum up the third column, but only until it exceeds 24 hours.

I understand that hours are handled like fraction of a day and I guess
I have to convert that fraction into a number.

At the same time I would have to keep the minutes as a fraction of an
hour, because otherwise the summing up would be confused?

TIA
Örjan Skoglösa