hi - i need to do a countif function that will count all the cells
that have a date on or before a certain date. i have a spreadsheet at
the very beginning that has this threshold date and want to reference
that cell in the count if function because it may be changing.

i have tried :
countif(firstcell:last cell,<=Worksheet1A1)

and have included paratheses but it always returns zero. both the
reference cell and the range with dates are set to mm/dd/yyyy.

Thank you!