determining if a set is well ordered set

Question

consider following question

I am able to easily see that set of positive rationals is not well ordered set but I have difficulty coming to conclusion with this

set of positive rationals with denominator less than 200

Is this well ordered set or not ?

I think it is well ordered set .If it is not, could someone give me non empty subset that is not bounded from below

another question regarding well ordered sets I read from wiki article that "the standard ordering ≤ of the integers is not a well ordering, since, for example, the set of negative integers does not contain a least element."I got that

Another relation for well ordering the integers is the following definition: x ≤z y iff (|x| < |y| or (|x| = |y| and x ≤ y)). This well order can be visualized as follows:

0 −1 1 −2 2 −3 3 −4 4 ... 

how can this be well ordered set, when we use argument same as above

consider set of negative integers -1 -2 -3 -4 -5 but this is not bounded from below, so how can this be well ordered set

Answer 1

Hint:

Reduce all these rational numbers to denominator $200!$.