I have a keyboard with an Apple/Mac layout (Option and Command instead of Alt and Windows keys), but I can't get its number keypad to work. I was able to figure out that the number keys are being used as a directional pad (4 as left, 6 as right, etc.) I found some advice online to press fn+F6 twice to change the numpad's behavior but it doesn't do anything.
Figured it out and thought I'd save someone else the trouble.
The clear key in the numpad (in the top left) functions as a numlock on this keyboard (the key that regulates how the numpad functions). Press the key to toggle between the numpad's two functions (as numpad and as directional pad).