Have you ever experienced opening a CSV by double-clicking it, only to find that 007 became 7, 4901234567890 became 4.90123E+12, or product codes turned into dates? The tricky part is that it has ...
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.