Arithmetic operations in BASH

arithmetic.sh

#!/bin/bash

echo "Enter your first number"
read x

echo "Enter your second number"
read y

(( prod=x*y ))  # Multiplication
(( quot=x/y ))  # Division
(( sum=x+y ))   # Addition
(( dif=x-y ))   # Subtraction
(( pow=x**y ))  # Power-of
(( mod=x%y ))   # Remainder

operations=(
    "Add" 
    "Subtract" 
    "Multiply" 
    "Divide"
    "Power-of"
    "Modulus"
    "Exit"
    )

select opp in "${operations[@]}"; do
    case $opp in
        "Add")
            echo "$x + $y = $sum"
            ;;
        "Subtract")
            echo "$x - $y = $dif"
            ;;
        "Multiply")
            echo "$x x $y = $prod"
            ;;
        "Divide")
            echo "$x / $y = $quot"
            ;;
        "Power-of")
            echo "$x ^ $y = $pow"
            ;;
        "Modulus")
            echo "$x % $y = $mod"
            ;;
	"Exit")
            echo "User requested exit"
	    exit
            ;;
        *)
            echo "invalid option $REPLY"
            ;;
    esac
done

echo ""