Examine whether the following statements are true or false :

$\{ a\}  \in \{ a,b,c\} $

The number of proper subsets of the set $\{1, 2, 3\}$ is

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

$\{1,2,5\}\in A$

Two finite sets have $m$ and $n$ elements. The total number of subsets of the first set is $56$ more than the total number of subsets of the second set. The values of $m$ and $n$ are

Write the following as intervals :

$\{ x:x \in R, - 12\, < \,x\, < \, - 10\} $

For an integer $n$ let $S_n=\{n+1, n+2, \ldots \ldots, n+18\}$. Which of the following is true for all $n \geq 10$ ?