How do you return a nested function in lua?

See more:

Lua

function BasicMath()
    function Add(a,b)
        function Subtract(a,b)
            function Mutiply(a,b)
                function Divide(a,b)
                    end
                end
            end
        end
    end

Hello i'm trying to return a nested function but i don't know how to does anyone know how to return a nested function? thanks for your Help :)

What I have tried:

I tried searching google and found no good results for returning a nested function