Let Excel prompt for error messages when data is entered incorrectly

After you set the data validation for a cell, an error message is displayed when invalid data is entered. The method for prompting for error messages can be customized by setting the following method.

(1) Select the range of cells for which data validation is set. Click data → effectivity to open the Data Validation dialog box.

(2) Select the Error Warning tab and enter the information shown in Figure 7-7 in the title box and the error message box, respectively.

(3) Click the OK button to return to the document, and when you enter a value less than 100 in the selected cell, the error message pops up as shown in Figure 7-8.

(4) You can also select the Input Information tab, set the display input information when you select a cell, and then when you move the mouse pointer over a cell that is set to be valid, you are prompted for the input information that you set.