T. Valko wrote...
....
Better to use cells to hold the criteria:

C1 = 1
C2 = A

=SUMPRODUCT(--(A1:A10=C1),--(B1:B10=C2))
....

Could take advantage of the adjacency of the data ranges and enter the
criteria in C1:D1, then try

=SUMPRODUCT(--(A1:B10=C1:D1))