XLS files are Excel workbook files created in Excel 97 or Excel 2003. The 2007, 2010 and 2013 versions of the program use the XLSX format by default to save workbooks, but can also use the XLS format.

Spreadsheets: love them or hate them, they are a part of modern-day life and Microsoft’s Excel software is the go-to for most users spreadsheet needs. But what happens when you want to edit a ...