There are three methods to represent a set. :
1. Statement Form
2. Roster / Tabular Form
3. Rule of Set Builder Form
Roster/Tabular form
Here, the elements of the set are listed within the pair of brackers {} and are separated by commas.
Thus, the answer to the question G = { x|x is a 3-digit number less than 100 } is
G = { -100, -101, -102, -103 ... -999}
Only negative 3 -digit number will be less than 100. Thus the set is the numbers from -100 to -999.