If you’re new to Excel, or even if you have some experience with it, you can walk through Excel’s most common formulas in this tour. With real-world examples and helpful visuals, you’ll be able to Sum, Count, Average, and Vlookup like a pro.

In File Explorer under View, in the Show/hide group, select the File name extensions check box. Below is a list of common Windows file name extensions and formats. Learn what file name extensions are, which extensions are common in Windows, and how to view them in File Explorer.