Look up any Excel function — syntax, a real example, and when to use it.
Returns TRUE if a cell is completely empty, and FALSE otherwise.
Returns TRUE if a value is any kind of error (#N/A, #VALUE!, #REF!, and others), and FALSE otherwise.
Returns TRUE only if a value is specifically the #N/A error, and FALSE for anything else, including other error types.
Returns TRUE if a value is a number, and FALSE otherwise.
Returns TRUE if a value is text, and FALSE otherwise.