A more useful Numpad on Linux

I put this into my ~/.bash_profile

xmodmap -e "keysym KP_Add = comma"
xmodmap -e "keysym KP_Divide = BackSpace"
xmodmap -e "keysym KP_Multiply = Tab"

Now the numpad has a backspace, tab, and comma key! This makes it really useful for data entry in LibreOffice.