Hi, Barry,
Sorry if I posted this to the wrong forum. As you noted, it is quite difficult to find the right place. I chose to use Numbers for iCloud so the file would be accessible across devices. Having worked with Excel and Google Sheets, I thought I could figure out Numbers by reading the manual and searching for answers, but trial and error has so far resulted in error.
I don't see anything under the wrench that gives me hope.

I searched support on "Numbers for iCloud unhide hidden rows" and eventually found Filter data in a table, and then I had to find the Sidebar.

When I click on Filter Table, it appears that no filter has been applied; at least there is no Cancel Filters button.

The instructions detail how to add a filter. At the end, it explains ho to turn off or delete a filter. However, there are no filters to turn off or delete.
Today, after having added more rows, rows 2-22 are hidden. Uh-oh, the more I add, the less I can see?