Excel has a function to change the format according to cell values and various conditions. Here is an example of a specific setting. Suppose you have a simple table like the one below, and you want to shade in red the cells where no sales have been entered. First, select the range you want to format. Next, select "Home"...

When using the pull-down entry function in Excel with the default settings, if you try to enter an item that is not in the list prepared for entry, an error message like the one shown below will appear and you will not be able to enter the item. In such a case, you can either allow any item to be entered, or display a message...