Subtracting time values

[Bill Wallace]

Looking through the time function, I see that it is possible to sum  
two different time values as for billing, say 4hrs & 30 plus 2hrs. Is  
it possible to subtract time as in the following example. A student  
checks in at 3:30 and leaves at 5:45. Is it possible to subtract to  
reach the time they were in extended day as 2 hrs and 15 minutes.
I am trying to automate the extended day billing at our school.
Thanks for any suggestions,

Bill Wallace


Bill Wallace
Librarian
Manzano Day School
Albuquerque, NM  87104
School email - bwall...@manzanodayschool.org