Display blank on formula error I'm making a timesheet.
I have =sum (A2-A1) but I have more than one task a day and not all times are used. The cells without time in them result in an error with the formula. Which, in turn, choses the day totals to show an error also. 



How can I show a blank cell instead of the error?
Use the IFERROR() function.

IFERROR(SUM(A2-A1),"")

If the cell calculation is valid, the calculation is displayed.  If there is an error in the cell, then this just returns "". (blank)