Example 48. Compute the following and simplify:

        (a)  (b)  (c)

        Answers: (a)  (b) 

        (c) 

Example 49. Solve the following inequalities:

        (a)  (b)  (c)

        Answers: (a) 

        (b)  (c)

Example 50. Illustrate the following properties of rational numbers with an example:

        (a) closure (b) commutativity (c) associatively (d) identity (e) inverse:

        Answers: (a) closure: 

        (b) commutativity :

        (c) associatively :

        (d) identity :

        (e) additive inverse :