Chapter 4.3, Problem 6E

(a)

To determine

Five different elements of $A=\left\{\frac{m}{n}\in Q|3\cancel{|}n\right\}$ at most one of which is an integer.

(b)

To determine

To prove: That $A=\left\{\frac{m}{n}\in Q|3\cancel{|}n\right\}$ is closed under addition.

(c)

To determine

To prove: That $A=\left\{\frac{m}{n}\in Q|3\cancel{|}n\right\}$ is closed under multiplication.