I think it is fair to say that any key that has a visual indicator associated with it, when the indicator is lit up, it tells the user the function of that key is on and active.

What exactly are you trying to type - using the Numlock + Alt + numerical keys on the pad allows a user to get Special Characters (Alt Codes)

Have a look at this link:

Special Characters — Alt Keyboard Sequences

https://tools.oratory.com/altcodes.html

Scroll to the bottom of the page see how to use this function.