Hi all, i'm having a little trouble getting this to show a value:

=SUMPRODUCT(B1:B10)*(A1:A10=LEFT(Sheet1!A1,FIND(" ",Sheet1!A1)-1))

On sheet1 A1 is constructed like this "Mon January" (without the quotes) in sheet 2 range A1:A10 i some cells just Mon and some with other text after it, however the SUMPRODUCT returns 0 but should return a sum of all those cells in column B that have Mon in the corresponding cell in column A.

Any ideas?