How to control the width of a number?

[Peng Yu]

Hi,

I want $page has three digits. If it is less than 100, prefix it with
0. Is there an easy way to do so in bash?

for i in `seq 28 55`;
do
  page=`echo '148-('$i'-28)*2'|bc`
  echo $i $page
done

-- 
Regards,
Peng