public String multip(String num,char n){
        String result ="";
        int val = 0;
        for(int i =num.length()-1 ;i>=0;i--){
            val = (num.charAt(i)-'0') * (n -'0')+ (val/10) % 10;
            result =  val%10 +result;
        }
        return result;
    }