Using Move, Copy or Delete Sheet

You can Close a document either with the Close command from the File menu or, more conveniently, by using the Close button on the document title bar. You will be asked if you want to save changes. 

If you hold down the SHIFT key while you pull down the File menu, the Close command becomes Close All. That way you can close all open Excel documents at once. 

When you use the Exit command (Windows) or the Quit command (Macintosh), you close all open documents (you will be asked if you want to save changes) and then exit from Excel. 

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