File type: Microsoft Excel Open XML Document
XLSX is a spreadsheet format that was introduced by Microsoft Excel 2007 which came as a part of the Microsoft Office Suite 12.
These files store the data in the cells and organize them in rows and columns as a table. These spreadsheets can be created with the help of Works 8.0 but can also be created by Microsoft Excel.
The XSLX format of the spreadsheet is based on the Open XML format and has a ZIP compression for smaller file sizes. These files are not directly backwards compatible with Microsoft Office 2000, or Office XP or even Office 2003 but they can support it using component support.