Do this:
- Right click the column A and then click "Format Cells"
- At "Number" tab Select "Custom" category (the last one)
- At the text box, type 00, then click OK
- That should work: All numbers from 0 to 99 will have two digits, and page ranges will work fine.
- For the page range cases, I'd also recommend you to always put the single quote before typing two numbers (Ex.: '03-04 instead of 03-04). This way, you avoid Excel treating the input as a date format