So here's my situation.  And don't lynch me for this one either.  I just recently learned how to use VI.  Shocking, isn't it?  I never had time to learn it, as system administration was only a part of my job description. even though I'm the only sys admin on site.  Nano was my choice of editing text files as I didn't need anything elegant for a quick modification of a conf file.
I chose to learn vi so I could develop websites on a terminal without firing up a VNC session - and wasting screen real estate in the process.  Vi with syntax highlighting just can't be beat.  A quick trip through vimtutor, a couple of Googles for setting up my .vimrc file, and I'm in business.  But, I digress.
The Problem
When on a Windows computer, I use Putty to access my Linux computer.  The number pad works just fine on the command line.  It was only when I started using Vi that I noticed when you attempt to use the keypad, Vi interprets them as a different series of keystrokes.  Not being able to use the 10-key is a big problem in my book.
The Solution
So, here's the solution.  In Putty settings, go to Terminal - Features.  Check the 
Disable application keypad mode and apply the setting.  The 10-key in Vi now works as expected!
My .vimrc file
For those that are interested, these are my basic Vi settings.
~/.vimrc
hi Comment   ctermfg=darkcyan
set ruler
set showcmd
set tabstop=4
set linebreak
Enjoy!
-- DRH