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.
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Why the XLS format needs to disappear from your hard drive forever
Upgrade to XLSX for smaller file sizes, enhanced security, modern collaboration features, and to prevent accidental data loss.
The cells in a Microsoft Excel spreadsheet can hold various types of numerical data, including fractions and percentages. If some or all of your cells contain fractions, Excel enables you to convert ...
Number formats in Microsoft Excel define how data is displayed in your spreadsheet without changing the underlying values. As well as using number formats to present data as dates, times, percentages, ...
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