How can I make this code work so that multiplying "\*" and mod "%" don't get an error message? I'm thinking is because they have special meaning to the shell. How would I take that away? 

```
#!/bin/bash

echo "Enter Number Operator Number"
echo "[Operators +, -, /, *, %]"
echo -n " --->   "

read num1 op num2

case $op in

  +) printf "$num1 + $num2 = %d\n" `expr $num1 $op $num2`

     ;;

  -) printf "$num1 - $num2 = %d\n" `expr $num1 $op $num2`

     ;;
  /) printf "$num1 / $num2 = %d\n" `expr $num1 $op $num2`

     ;;

  \*) printf "$num1 * $num2 = %d\n" `expr $num1 $op $num2`

     ;;
  %) printf "$num1 % $num2 = %d\n" `expr $num1 $op $num2`

     ;;

  *) echo "Bad Operator: $op choose [+, -, *, /, %]"

     ;;

esac

```