#!/bin/sh

sum=10
n=0
for n in 0 3 8; do
n=`expr $n + 1`
sum=$(echo "$sum + $n" | bc)
mean=$(echo "scale=4; $sum / $n " | bc)
echo $n $sum $mean
done


=============================
kondo@kondo-PC ~/shell
$ source decimal_fraction.sh
1 11 11.0000
4 15 3.7500
9 24 2.6666