Shell Scripting Arithmetic Operations

#!/bin/bash

#arithmetic operations

a=10
b=20

echo "a = $a b = $b"

val=`expr $a + $b`
echo "a + b : $val"

val=`expr $a - $b`
echo "a - b : $val"

val=`expr $a \* $b`
echo "a * b : $val"

val=`expr $b / $a`
echo "b / a : $val"

val=`expr $b % $a`
echo "b % a : $val"

readonly n=100

total=`expr $val + $n`

echo $total

#n=$total

#echo $n

#floating point arithmetic

x=10.1
y=20.2

echo "$x + $y" | bc
echo "$x - $y" | bc
echo "$x * $y" | bc
echo "$x / $y" | bc