If you've used data validation in Excel before, you probably selected the relevant cells, clicked "Data Validation" in the ...

Excel's conditional formatting tool applies formatting depending on cells' contents. Validation rules can change cells font, style, size or border. They can also change the text's color. For example, ...

Validation is an automatic computer check to ensure that the data entered is sensible and reasonable. It does not check the accuracy of data. For example, a secondary school student is likely to be ...