MX5500 Keyboard has no Numlock key

I use the Logitech MX5500 Keyboard at work and at home. 849,020 keystrokes later and I still like it’s handy LCD panel with useful information. Right now, the room is 26°C! The unfortunate part is that there is no numlock key. To toggle the numlock, I first install numlockx:

sudo apt-get install numlockx

When I need to make the switch (I actually just keep numlock on, this is for the odd times my machine loads and numlock is off):

numlockx toggle