# Question #6c402

##### 1 Answer

Dec 31, 2016

The set is countable (countably infinite) and unbounded.

#### Explanation:

The rationals are countable.

The set of ordered pairs of elements of a countable set is countable. (More generally, the Cartesian product of two countable sets is countable.) (Use a proof analogous to the proof that the rationals are countable.)

So, the ordered pairs of rationals are countable.

So,