4.整数的各位积和之差

 <script>
        var n = 234
        var a = 1;
        var b = 0
        var m = String(n).split("")
        for (let i = 0; i < n.length; i++) {
            a = a * Number(m[i])
            b = b + Number(m[i])
        }
        var x = a - b
        console.log(x)
    </script>