How to check between a string and a number?

So if I make a Stat Editor Gui for as a Devloper Gui in my game i want to see if I put string it would put and error and if i put a number then it won't get and error and it will give the player whatever i would put but i don't get how to check between a string and a number?

Do this:

if typeof(thing) == "number" then
	-- code
elseif typeof(thing) == "string" then
	error("Typeof " .. thing .. " is a string.")
end

make sure to define thing!