To enable numlock in Gnome (<3.36), it's a bit trickier, but should be easy enough! You'll have to have Gnome Tweaks installed (any Gnome user should def have this if they don't already, it's in the SC). In Gnome Tweaks go to Keyboard & Mouse tab then under keyboard click "Additional Layout Options" which opens a new window. Click the third sub-menu called Miscellaneous Compatibility Options, and check the box called "Numeric Keypad Always enters digits (as in MacOS)" There are a few other numlock options within that sub-menu, so there's a few different ways to tweak it, but that's how I do it in Gnome so have the numlock always on when I restart or login, it's on and I'm good to go!