Remove hyperlink formatting from address
In the Numbers 3.5.3 this is extremely difficult to do. Thanks to @Vev for giving me the hint to discover how to do it.


First: expand the size of the cell so there is some white space
around the hyperlink. 
Click once in the white space to select the
Cell. 
Click once again in the white space, to enable the Text Cursor.
Right-Click on the hyperlink, which selects it and provides a context
menu. (If you don't have right-click enabled, use Ctrl-click on the
Mac) 
Select "Edit Link" in the context menu. 
Click the "Remove" button from the Edit Link dialog.