Which of the following are sets ? Justify your answer.

The collection of questions in this chapter.

Consider the sets

$\phi, A=\{1,3\}, B=\{1,5,9\}, C=\{1,3,5,7,9\}$

Insert the symbol $\subset$ or $ \not\subset $ between each of the following pair of sets:

$A, \ldots B$

Let $A=\{1,2,3,4,5,6\} .$ Insert the appropriate symbol $\in$ or $\notin$ in the blank spaces:

$ 2 \, ....... \, A $

What universal set $(s)$ would you propose for each of the following :

The set of right triangles

Write down all the subsets of the following sets

$\emptyset $

Write the following intervals in set-builder form :

$\left( { - 3,0} \right)$