Excel's error values indicate why a formula could not succeed: #N/A (value not found), #DIV/0! (division by zero), #VALEUR! (#VALUE!, wrong type), #REF! (deleted reference), #NOM? (#NAME?, unknown function name or text without quotation marks). Each one guides the diagnosis of the cause.
Example
=A2/B2 returns #DIV/0! when B2 is 0.