How do you specify in a formula to count all cells in one column if values in
another column match a value in a particular cell and sum the totals across
worksheets. I have tried this formula but something is amiss at the last
step. I wanted to only count a value if a date in column M matched the date
in cell B1.

=SUMPRODUCT(COUNTIFS(INDIRECT("'"&A22:A43&"'!n3:n6 1"),"0",INDIRECT("'"&A22:A43&"'!m3:m61"),"2/28/10",INDIRECT("'"&A22:A43&"'!m3:m61"),"<4/1/10",INDIRECT("'"&A22:A43&"'!M3:M61"),INDIRECT("'"& A22:A43&"'!B1")))