Subtotal filtered columns
People coming from the competing platform will look for a function to automatically display only a subtotal rather than the total of all the rows, including those hidden. Quite a few on long since closed discussions suggest workarounds that are not likely resorted to.
However, while sometimes you just want, without changing the entire look of your spreadsheet, that simple extra footer row with the subtitle to automatically only show the visible rows according to whichever the quick filter chooses to be visible, a major feature in Numbers leapfrogs Excel and specialises in giving you subtotals and the overall total, if you can stand the layout difference.
On the other hand, reverting to Excel or the like will lose the far nicer formatting of Numbers, so revert as infrequently as possible!
The quickest workaround is to simply select the individual cells in the table that you want to add up. It can be a contiguous range or individual cells (using cmd and click), and in the far bottom of Numbers you will have displayed Sum, Average, Min, Max, and Count!
On the Organise menu choose Categories and explore what you can do as the first resort to getting ad hoc subtotals. Otherwise, for the not-so ad hoc, more intricate workarounds, with separate tables grabbing sub-totals from the main table can be tried.
If you know how to get the basic feature of a subtotal in a cell, showing the ad hoc visible results of a quick filter then by all means let us know.
Mac Pro