Find the average of two numbers entered as command line arguments |Shell Program|

#!/bin/bash
n=$#
sum=0
for i in $*
do
sum=`expr $sum + $i`
done
avg=$(echo "scale=2;$sum / $n" |bc)

echo "average=$avg"


OUTPUT
 NB: please enter two values at the run time

./average.sh 4 2
average=3.00