Explanation

Spreadsheets are typically saved with the file extension ".xls" or ".xlsx" when using Microsoft Excel, ".ods" when using OpenOffice Calc, ".csv" when saved in comma separated value format and ".tsv" when saved as tab separated value format.

The ".xls" extension is used for older versions of Microsoft Excel, such as Excel 97-2003, while the ".xlsx" extension is used for newer versions of Excel, such as Excel 2007 and later.

The ".ods" file format is used for spreadsheets created in OpenOffice Calc, which is a free and open-source alternative to Microsoft Excel.