Try this:

Assuming A2 is a true Excel date.

=IF(ISNUMBER(A2),500,A100+B100)

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Biff
Microsoft Excel MVP


"Dave" wrote in message
...
Hi all,

I need a formula to work on my sheet that if a date is put in the cell a2
for example I want the cell the formula is in, to display *500*. If no
date is put into the cell a2 then I want the cell to calculate the sum
part of the formula.

I've had a number of goes with limited experience and no success.

If (a2=0, sum(a100+b100, "500")

Any ideas people?