Forest for the trees moment. I assume this is not a num lock go put on?
Remapping wise it is more the keyboard settings might not be the ones it wants -- in my case I usually see it for US keyboards vs UK keyboards (£ on the keyboard and @ above the right shift, with £ being a rather useful thing to have on UK keyboards as it is the currency symbol).
Afraid I don't know what goes around you but it is not unheard of for things to output data it has no idea what to do with if it is the wrong setting.
You don't map things generally. You can do various things (
silly example) with some of the things people use to do macros. Here you can have something run to note you are pressing some other combo or button and have it sub in something else but that is not a great fix and runs the risk of training you to do something else which can be tricky when you get a new keyboard.
If you have disassembled the laptop recently or dropped the thing then the cable might have come loose but I doubt it (and again usually a block of keys will stop here). If you know what you are doing then you can try reseating it; it is usually not difficult, usually either some screws or some plastic trim to remove to get at it but can vary dramatically, and modern consumer stuff can be even more annoying should you have to replace it.
Anyway dirt can be a fun one, and keys stopping working can also be the result of someone spilling things on the keyboard (though again it is usually selections of keys not working any more, them firing randomly, or them repeating lots).
If it is not a rock stopping it from being pressed and a token squirt with some electronics safe (not automotive) contact cleaner does not do it then yeah dead key, time to replace the keyboard or live with a workaround. It is one of the major downsides of laptops.