=SUM(IF(ISNUMBER(C672:C678-D671:D677),C672:C678-D671:D677))+IF(ISNUMBER(D678-C678),D678-C678)


Entered with Ctrl+Shift+Enter rather than just enter (since this is an array
formula)

should work.

--
Regards,
Tom Ogilvy



"Rob" wrote in message
...
I have this formula that subtracts one cell from another and then adds that
to a running total.

=(C672-D671)+(C673-D672)+(C674-D673)+(C675-D674)+(C676-D675)+(C677-D676)+(C678-D677)+(D678-C678)


My problem is this; on occasion there will be the need to have some cell
pairs blank or they'll contain "N/A" in them. When this happens I get a
Value
error. How can I correct this?


Thanks in Advance,
Rob