In a helper column you can have a formula like this:
=IF(LEN(A1)=3,"Yes","No")
or like this if your numbers are proper numbers:
=IF(AND(A1>=100,A1<1000),"Yes","No")
Copy the formula down the helper column, then apply autofilter to that
column, selecting Yes from the filter pull-down.
Hope this helps.
Pete
Thank's,