If you see a particular error in your sheet, select the cell and go to the “Formulas” tab. Click “Error Checking” in the Formula Auditing group. You’ll see the Error Checking window appear with brief details on the error. You can choose to get help with the error from Microsoft on the Web, show the calculation steps, ignore the error, or edit the formula.
Additionally, you can visit the How to Avoid Broken Formulas page on the Microsoft Support site for a list of common formula errors with descriptions.