Excel File Extensions

I have an Excel file that when I opened it shows multiple extensions of that file.

Example the file 03-2002fs.xls when opened, it will display:
03-2002fs.xls:1
03-2002fs.xls:2
03-2002fs.xls:3
03-2002fs.xls:4

So my question is, how did I get those extensions and how do I delete them?