Hay, guys,
Any ideas how to calculate like this:
in first file, there're number of lines listing 2+3, 6*9 .......
Then, how to get the result and put them in another file in format:

2+3 5
6*9 54

......

sheerly by shell command, no scripts required.

sed 's/\*/\\\*/' file1 > dummy
sed 's/\//\\\//' dummy > file2
while read line
do
echo "$line \c" >> Output
echo "$line" | bc >> Output
done < file2

The way the question is phrased I tend to think that we may have homework rule violation here.
But:
bc < input > temp ; paste input temp > output ; rm temp

Thanks Perderabo,
I think you answer is fairly enough. vgersh99&justsam's genius work is also appreciated.