Write the following set in roster form:
$\left( i \right)$ The set of the first five odd counting numbers.

Hint: As we know that the odd numbers are those numbers which are not divided exactly by $2$ . Therefore, for the first five odd numbers, the number will start from $1,3..$ . And also we know that to compose a set in roster form, we should simply list every component of the set, isolated by commas, inside a couple of curly braces. So in this way, we can easily write in roster form.

Complete step-by-step answer:
First of all, we will write down the first five odd numbers. So the odd numbers are
$1,3,5,7,9$ . Now we have to write it in the roster form.
As we already know how to write in roster form. So the roster form for the given question will be written as-
Therefore, the above set in roster form will be- $\left\{ {1,3,5,7,9} \right\}$ .
Hence, $\left\{ {1,3,5,7,9} \right\}$ will be the set of the first five odd counting numbers.

Additional information:
Here, it should be noted that when there are some random numbers given in the sets then the sets are unordered and we can write the elements of it in any order while writing in roster form.

Note: There are mainly two forms in which sets are written. One is the roster form and the other one is the set builder form. As we have already known the roster form so set builder forms are those forms of sets in which the elements are written in statements like we have the statement in the question. In this way, we can know the difference between these two forms of the set.