If a user tries to open a Workbook that is already open, then they normally get a message saying that the File is locked by a certain user and would you like to open the file in Read only mode. However, you can open a workbook in shared mode by following these steps. First open the file that you want to share, then once the workbook is open, go to the Tools menu and choose Share Workbook from the drop down menu. The Share Workbook dialog box will now appear. To enable sharing, you simply click once on the Allow Sharing check box, so that it has a tick. Once you do this other people will now be able to use your Excel workbook whilst you are working on it.
If you are relatively new to using Excel, you will notice that learning to use all Excel formulas is no easy task. There are many different functions that can be accomplished by the use of these formulas such as mathematical calculations. This is not something you can accomplish by listing your data on a Word document. The simplest of all Excel formulas are those used to perform basic mathematical calculations such as addition, subtraction, division and multiplication. If you have never worked inside of an Excel spreadsheet, you are going to need to find a course that can teach you how to get started. These functions are among the most basic and are quickly learned by even the most inexperienced users.