Glad to help

--
Don Guillett
Microsoft MVP Excel
SalesAid Software

"Fred Loh" wrote in message
...
It works! Thanks Don.

"Don Guillett" wrote:

Sumproduct does not take full columns. Must use a range as I did a2:a???

--
Don Guillett
Microsoft MVP Excel
SalesAid Software

"Fred Loh" wrote in message
...
thanks guys!

Gary's Student's solution works and the logic makes sense.

Teethless mama's solution also works but I don't understand why the
need
to
multiply {1,-1}

i can't get Don's solution to work. i have a "#NUM!" error.