Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?

$1 \subset A$

Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?

$\varnothing \subset A$

Assume that $P(A)=P(B) .$ Show that $A=B$.

Which of the following pairs of sets are equal ? Justify your answer.

$\mathrm{X} ,$ the set of letters in $“\mathrm{ALLOY}"$ and $\mathrm{B} ,$ the set of letters in $“\mathrm{LOYAL}”.$

Write the following sets in roster form :

$B = \{ x:x$ is a natural number less than ${\rm{ }}6\} $

Write the following sets in roster form :

$A = \{ x:x$ is an integer and $ - 3 < x < 7\} $