I have this formula below it will count the uniques in column B & C in
the entire workbook. NOT per indivual worksheets.

=SUM(N(FREQUENCY(Sheet2:Sheet3!B2:C100,Sheet2:Shee t3!B2:C100)0))

My question is can the formula above look in column A and find the
text "a" and compare the columns B & C and then sum up in column D ?

I also posted he click the link below to see the example what I'm
looking for.

http://www.mrexcel.com/board2/viewto...627&highlight=