Ubuntu: Numlock Keypad Not Working

System > Preferences > Keyboard

If you're using Ubuntu, and num lock isn't letting you use your number keypad, here's what to do:

1. Click on the System Menu 
2. Go to Preferences sub menu 
3. Select Keyboard 
4. Click on the Mouse Keys tab 
5. Uncheck "Pointer can be controlled using the keypad"

The keypad should now behave as expected when numlock is on.

Ctrl-Shift-NumLock

I know on my computer the numlock key can get disabled by wrong key combinations. Your keyboard recognizes you are typing the numlock key. Try Ctrl-Shift-NumLock and see if that restores it.

References

Ubuntu Numlock Keypad Not Working by Michael Phipps
Thread: [SOLVED] num lock quits working on hardy Ubuntu Forums