function getSymbol(numbers, result)

local function explode(e, sep)
    local result = {}    e:gsub("[^".. sep .."]+", function(s) table.insert(result, s:match("^%s*(.-)%s*$")) end)
    return result
end

 local s = {"+", "-", "*", "/", "^"}
 local exp = explode(numbers, " ")
 local ret = nil

for sig = 1, #s do
    local v = loadstring("return " .. exp[1] .. s[sig] .. exp[2])()

    if v == result then
        ret = exp[1] .." " .. s[sig] .." " .. exp[2] .. " = ".. v
    end
end

    return ret
end