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Excel Secrets Validation of input data.

As a matter of fact, filling out even the most complex spreadsheet is no problem. It is much more difficult not to make mistakes at all. Indeed, you must admit that it is not difficult to make a mistake by typing, for example, 1899, instead of 1999, or making a mistake in a set of impressive numbers. In the popular Microsoft Excel spreadsheet processor, there are several tricks that make it easy to enter data and also automatically check for correctness.

When entering numerical data, it is allowed to set a range of conditions for checking the entered values. In this case, for each entered value, a check will be carried out whether it pleases in the specified interval. If this condition is not fulfilled in any way, a message appears on the screen stating that the entered value does not fit the specified restrictions.
In order to set the condition for checking numerical values, it is necessary to select the range of cells where numbers will be entered, and also select "Data -> Check". In the "Data type" field, you need to set integers or real ones, depending on what exactly is planned to be placed in the cell. The type "valid" is used for decimal numbers. A logical condition is indicated below in the field “value”, for example, “between”, “more”, “more or equal”, “not equal”. The last pair of fields is intended for numerical values ​​with which the input data will be compared.

Here the conditions for checking numerical values ​​are set.
Excel seems to make it easier to enter data that is repeated. Enter all the name data in a separate county worksheet. Later on, having selected the range of future verification of values, select "Data -> Verification", in the "Data Type" field, set the value to "List". Below in the line "Source" you need to specify the addresses of the cells in which this list is located.

When using the list for data entry, you must specify the address of the range in which it is located.
As a result of these actions, you don’t need to enter text in the selected cells: when the cell is activated, a list will appear next to it, from which you just need to select the desired value.

Instead of entering data, it is now allowed to select them from the list.
Another convenient solution: in Excel, you can eat the ability to set the display of prompts next to the cell when entering data into it. To do this, in the "Validation of Entered Values" window, go to the "Message for Entry" tab and also type a message that will appear when entering data into the cell. It will be convenient to use the switch "Display tooltip if the cell is current."

A hint will help you indicate exactly what is being entered into the cell.
On the tab "Error message" it is allowed to control the appearance of a standard system message that tells the user that the data was entered incorrectly. You can disable its appearance (uncheck the box "Show error message"), only it seems that you can set your own text for this message in the "Title" and "Message" fields.