Number Splitter

function split(x)
    local tab = {}
    for i=1,#x do
        local num = string.sub(x,i,i)
        for k=1,#x-i do
            num = num.."0"
        end
        if tonumber(num) ~= 0 then
--          if num ~= "50" and num ~= "5" and num ~= "500" then
                local numberofzeros = #num-1
                for i=1,tonumber(string.sub(num,1,1)) do
                   local newnum = 1
                   for i=1,numberofzeros do
                       newnum = newnum.."0"
                   end
                   table.insert(tab,newnum)
                end
--          end
        end
    end
    return tab
end

local a = ""
local k = split("396")
for i=1,#k do
    if i ~= #k then
        a = a..k[i].."+"
    else
        a = a..k[i]
    end
end

print(a)