local sum = function(arrays)
    local sum = 0
    for _, array in ipairs(type(arrays) == "table" and arrays or {arrays}) do
        for _, number in ipairs(array) do
            sum = sum + (tonumber(number) or 0)
        end
    end
    return sum
end

local meta = function(...)
    local metatable = {}
    metatable.__add = function(this, other)
        return setmetatable({sum({this, other})}, metatable)
    end
    metatable.__call = function(this)
        return this[1]
    end
    return setmetatable({...}, metatable)
end

local x = meta(1, 5, 10)
local y = meta(100, 500)
local z = meta(304, 41, 90, 69)

print((x + y + z)()) --> 1120