I am using the following =SUMPRODUCT(--(MONTH(A$3:A$87)=1)) to count the
number of transactions for the time period. When I change the Month number
to 2 the formula calculates correctly. However, for Month = 1, the formula
is counting all the blank cells in the column as 1 also (I saw this using the
formula auditing feature). A fix would be appreciated but I would also like
to know why?

On a related topic, is there a way to use the Month feature to determing Max
& Min values for the specified time period?