How to set up 10 key

By chance do you have any third party antivius, cleaning or any other similar products installed?

Please restart the computer in Safe Mode per the directions in the  How to use safe mode on your Mac - Apple Support link. 

Note: If you are using a wireless keyboard please either plug it in using the supplied Lightning cable that shipped with it. If you are using a legacy keyboard or a third-party keyboard that does not have re-charging abilities, please use any USB keyboard. Also note that a Safe Mode restart may require you to hold down the shift key for up to 5 minutes before the computer starts in Safe Mode. You will know it is in Safe Mode when you see “Safe Mode” in the upper right of the display.

After restarting in Safe Mode, then restart normally and test.

It will help us get a good idea of what is causing your problem if you provide a report of your system, that way we do not have to play 20 questions with you. The report we are requesting does NOT provide any personal information and is extremely safe to use. Please navigate to www.Etrecheck.com and download the free version of EtreCheck. Once you have you downloaded the app and installed it, please run the report and save it.

When you have your report, you can attach it when you reply to this message and we can then review it and help you determine what is needed to get your system running well again.

For instructions on how to download your EtreCheck report and attach it to your reply to this message please click https://discussions.apple.com/docs/DOC-250000211

The only major thing I see on the report is there is no indication you backup the computer but we will cover that later.

I do not see anything obvious that is causing your problem so you can first try resetting the SMC 2-3 times back to back and see if that helps.

To reset the SMC on M1 macs. You will click on the apple logo to shutdown the Mac. Unplug all wired connnections (including the keyboard and power on the Mac and test.

If the problem continues, please create another user account (call it TEST ACCOUNT) and then test the keyboard to see how it works. If it works okay then it's something you have to troubleshoot in your normal account. If it still does not work in TEST ACCOUNT please move onto the next step.

If the problem persists then I'd recommend trying another keyboard that has a 10 keypad and see if that works. If it does then there is a problem with the keyboard itself.

As for your backup. Please read Back up your Mac with Time Machine and begin using Time Machine to backup ASAP!! This is critical, not having a backup plan is a 100% guarantee you will lose data!!! You will need an external HD to backup to, many experienced users on these forums recommend the OWC Mercury Elite Pro due to it's high reliability, reasonable cost, support (both before and after the sale) and when the internal HD does die (they all do) you can easily replace the HD with another in less than 5 minutes.

Make sure Mouse Keys are not enabled.

Mac accessibility shortcuts - Apple Support

Are you using an Apple keyboard with a 10 keypad or a third party keyboard with a 10 keypad?