Let $A$ and $B$ be two sets in the universal set. Then $A - B$ equals
$A \cap {B^c}$
${A^c} \cap B$
$A \cap B$
None of these
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
$B-D$
The shaded region in given figure is-
If ${N_a} = \{ an:n \in N\} ,$ then ${N_3} \cap {N_4} = $
If $A$ and $B$ are two sets, then $A \cup B = A \cap B$ iff
Find the union of each of the following pairs of sets :
$A=\{a, e, i, o, u\} B=\{a, b, c\}$