You don't necessarily need Microsoft Excel to work with an .xlsx file Reviewed by Ryan Perian This article explains what XLSX ...

In the free open-source office suite Apache OpenOffice, Calc is the spreadsheet equivalent to Microsoft Excel. Calc allows you to open and edit files originally saved in other programs and formats, ...

Convert OpenOffice.org Calc spreadsheets into a Microsoft Excel file to take advantage of Excel's built-in tools. OpenOffice.org spreadsheets default to a .xsc file extension, which certain versions ...