John --
I understand you to be saying, "If the value in Column A is "abc", then
multiply the values in Columns B&C, and give me the sum of those products."
If so, here's one way:

A B C
1 abc 1 2
2 abc 2 4
3 def 3 5

=SUMPRODUCT(--(A1:A3="abc"),B1:B3,C1:C3)

Should return the answer of 10.

HTH

"John" wrote:

Not sure how to do this, I need to add Column A that equals "abc" then
multiply column B by Column C. There could be up to say 12000 cells in
column A. So what I need to do add up anything in Column A any cell that
equals the text value of "abc" then multiply the cells in column B by column
C. Hopefully that came out right.

Thanks in advance