You don't necessarily need Microsoft Excel to work with an .xlsx file This article explains what XLSX files are, how to open them, and which programs are able to convert them to other spreadsheet ...

How to Open an XLS File in Excel. 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 ...

What happens when you want to edit a Microsoft Excel .xlsx file on a Mac, iPhone or iPad? While it’s not quite as easy as opening .docx files in Pages for Mac, it’s not an overly complicated ...

Designed for use with Office 2000, XP, and 2003, the downloadable add-on allows you to open, edit, and save the newer file formats, seamlessly converting the files on the fly and in the background.