Find the number of subsets and the number of proper subsets of a set $X=\left\{a, b, c, x, y, z\right\}$.

If $P=\left\{m, n\right\}$ and $Q=\left\{m, i, j\right\}$, then, represent $P$ and $Q$ in Venn diagram and hence find $P\cup Q$.

If $A=\left\{-3, -2, 1, 4\right\}$ and $B=\left\{0, 1, 2, 4\right\}$, find $A-B$

If $A=\left\{-3, -2, 1, 4\right\}$ and $B=\left\{0, 1, 2, 4\right\}$, find

$B-A$