Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?
$1 \in A$
Examine whether the following statements are true or false :
$\{ a,b\} \not\subset \{ b,c,a\} $
The number of elements in the set $\{ (a,\,b):2{a^2} + 3{b^2} = 35,\;a,\,b \in Z\} $, where $Z$ is the set of all integers, is
Write the set $\{ x:x$ is a positive integer and ${x^2} < 40\} $ in the roster form.
Which of the following are examples of the null set
Set of odd natural numbers divisible by $2$