Allo all,
I use Kubuntu 20.10
I run it on 2 PCs. 1 PC runs Kubuntu 18.04. The hardware is different in each case.

Some sites recommend doing
sudo apt-get install numlockx
and reboot PC

That doesn’t do anything.

Some sites recommend
Start -> Applications -> Settings -> System Settings
On the left side, click on Input Devices -> Keyboard -> Hardware -> Numlock on Plasma Startup -> Turn On

but that turns on the Numlock only when you log in.

I saw a few websites about it, some are about Ubuntu, some are about Linux Mint and Debian.
They talk about files that don’t exist on Kubuntu 20.10.

Some sites recommend turning it on in the BIOS. It’s already on in the BIOS.
When I turn on the PC, the Numlock turns on and when Kubuntu is starting up, it turns it off.