The numeric keypad doesn’t work in a fresh Ubuntu install in Virtualbox ( possibly not related to Virtualbox but is one of the factors in my case )…

A bunch of Googling leads to two solutions that when put together, worked for me:

{Name} ( top right of screen ) -> System Settings -> Keyboard Layout -> Layouts Tab -> Options -> Numeric Keypad Layout Selection -> Select “Legacy”

This alone didn’t do the trick.  The next piece I found was to hit ctrl + shift + Num Luck.  You may have to hit that combo then type some numbers, try it again, type some numbers, etc etc.  Those two things together did the trick for me and now.. I can use the Keypad!