Question

the set of odd numbers less than

Answer 1

The set of odd numbers less than zeros.

This set would be \(\large\color{blue}{ \rm all~~negative~~integers }\) such as
-1, -3, -5, -7... and so on.

Less than a certain number, (lets say that this number if 7, then it would be
\(\large\color{blue}{ \rm 5,~~3,~~1,-1, -3,-5.... }\)

Answer 2

I don't really get what exactly you are trying to say though.