The number of non-empty subsets of the set $\{1, 2, 3, 4\}$ is
$15$
$14$
$16$
$17$
Write the following sets in roster form :
$\mathrm{E} =$ The set of all letters in the world $\mathrm{TRIGONOMETRY}$
Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?
$\{1,2,5\}\in A$
Let $A=\{1,2,3,4,5,6\} .$ Insert the appropriate symbol $\in$ or $\notin$ in the blank spaces:
$ 2 \, ....... \, A $
Which of the following are sets ? Justify your answer.
The collection of all natural numbers less than $100 .$
Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?
$\{ 3,4\} \in A$