Is there a function in Excel that will take cell fills and tally up the
count of each one to get a total of cell fills?

i.e., if we have a time sheet sort of spreadsheet, every time we put in "7.5
hours", or whatever, in a cell, tied in to a date, that a cell at the bottom
of the page that says "# of days worked" will calculate the total # of days
worked based on how many cells in the month were filled?

If so, what would this be called, pls? I could find code for doing this
type of thing if I could figure out what this type of thing was called.

Thanks much. :oD