keyboard help

Ok, thanks, that help with understanding what keyboard you actually have.

Since you have been having this issue with macOS Big Sur, and especially not resolved with Monterey, indicates that the issue is not necessarily related to the operating system. That would lead me to believe, that this may be a hardware/firmware issue with either the keyboard itself or with the iMac.

As such, I would suggest trying, at least, the following three things:

1. For Intel-based Macs, I would suggest that you reset the computer's SMC. Since you have an M1-based Mac, this doesn't apply and simply restarting the Mac should perform the same thing.
2. Double-check your current keyboard settings @ System Preferences > Keyboard to be sure the correct keyboard is being "seen" by your Mac.
3. Try another keyboard. If it works, then this would narrow down the issue to the current keyboard. If it doesn't either, then this would indicate a potential issue with the Mac itself.

farone1222 wrote:

I've tried the instructions I found online but nothing works.

Does that include checking your Accessibility preferences to make sure that nothing is turned on there, especially that Mouse Keys is turned OFF. Pressing Option 5 times may do that.

https://support.apple.com/en-ke/guide/mac-help/mchlp2366/mac

Keyboard is working fine but numeric pad won't work at all.

That is a very odd failure mode I've not heard of. As you've only had the computer for six months, it and its keyboard are still in warranty, and this is not sounding like some you can fix at home.

I would call Apple immediately and have them fix it.

It would help if you can provide us with the make & model of this "extended" keyboard that you are referring to in your post. We can only go by what you tell us. All we know, so far, is that you have a 21.5" iMac, running macOS Monterey and that this keyboard's numeric pad doesn't seem to work. Also, is this keyboard designed to work with Apple products?