One way:

=SUMPRODUCT(--(A1:A1000="Jan"),E1:E1000,F1:F1000)

In article . com,
Steve wrote:

Hi all. I have a column of Months in Col A (Jan-Dec). Conceptually,
I need to look down column A, and for every instance of "Jan",
multiply Col E by Col F, and then sum all the resulst. So
essentially, its a sum if. Bt instead of summing a single column, its
summing the multiplaication of 2 columns.

I know I can have a helper column. But this example is WAY
oversilmplfied. I would need about 12 helper columns, which I would
like to avoid if possible. Thanks!