-K (--rebindkeypad)To fix this system-wide for everyone, just add the following to /etc/nanorc (or, on Gentoo, uncomment the line as it's probably already there:
Interpret the numeric keypad keys so that they all work properly. You should only need to use this option if they don't, as mouse support won't work
properly with this option enabled.
Alternatively, add the line to your ~/.nanorc.
## Fix numeric keypad key confusion problem.