I. Write W if the set is well-defined and NW if not. Well-defined means, it must be absolutely clear that which object belongs to the set and which does not. examples:
_W_Set of even numbers.
_NW__ Set of best guitar players.
__1. The set of all red automobiles.
__2. The set of all good books.
__3. The set of odd numbers.
__4. Set of prime numbers
__5. The set of large numbers.​