Sometimes numeric pad seems to randomly stop working and numbers don’t type. If you are familiar most PC Keyboards, they have “Num Lock” keys but Apple Wired Keyboard doesn’t include that. Almost every occurrence where the number keypad has stopped working with a Mac keyboard, the resolution is easy.
There is not a dedicated Num Lock key on the Apple Wired Keyboards but you can use same function by tap the “Clear” button on the numeric keyboard. You may need to press “Shift+Clear” depending on your individual keyboard and settings. Try both of those separately, and then try to type numbers using the numeric keypad again, this should resolve the issue in most cases.
If the first solution doesn’t work for you you can try this one. This settings is called Mouse Keys, which allows a user to control onscreen cursor using the number pad on an extended keyboard.
Mouse Keys may be the reason the numeric keypad isn’t working is that when you type a number, the mouse cursor moves very slightly, thus if you try to type a bunch of numbers the mouse cursor on screen may seem to jiggle around a bit in a small area. This is not always very obvious though because the Mouse Keys feature is intended to be precise and allow for fine manipulation of onscreen elements, thus you should always check for the setting when troubleshooting the matter.