#! /bin/bash
string='';
sum=0;
for I
	do
	     if	[ $I -gt 0 ]; then
			sum=$(($sum+$I));
			string=$(echo "$string + $I");
		elif [ $I -lt 0 ]; then
			sum=$(($sum+$I));
			string=$(echo "$string - $I");
		else
			string=$(echo "$string + $I");
	fi
	done
echo "$string = $sum";