The shaded region in given figure is-
If $A=\{3,6,9,12,15,18,21\}, B=\{4,8,12,16,20\},$ $C=\{2,4,6,8,10,12,14,16\}, D=\{5,10,15,20\} ;$ find
$C-A$
If $A, B$ and $C$ are any three sets, then $A - (B \cap C)$ is equal to
Let $\mathrm{X}=\{\mathrm{n} \in \mathrm{N}: 1 \leq \mathrm{n} \leq 50\} .$ If $A=\{n \in X: n \text { is a multiple of } 2\}$ and $\mathrm{B}=\{\mathrm{n} \in \mathrm{X}: \mathrm{n} \text { is a multiple of } 7\},$ then the number of elements in the smallest subset of $X$ containing both $\mathrm{A}$ and $\mathrm{B}$ is
Consider the following relations :
$(1) \,\,\,A - B = A - (A \cap B)$
$(2) \,\,\,A = (A \cap B) \cup (A - B)$
$(3) \,\,\,A - (B \cup C) = (A - B) \cup (A - C)$
which of these is/are correct