Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?
$\{1,2,3\}\subset A$
Which of the following are examples of the null set
Set of even prime numbers
List all the elements of the following sers :
$D = \{ x:x$ is a letter in the word $"\mathrm{LOYAL}" $ $\} $
Write the following intervals in set-builder form :
$\left[ {6,12} \right]$
If $Q = \left\{ {x:x = {1 \over y},\,{\rm{where \,\,}}y \in N} \right\}$, then