Let S be the universal set, where:
$\displaystyle {S}={\left\lbrace{1},{2},{3},\ldots,{18},{19},{20}\right\rbrace}$
Let sets A and B be subsets of S, where: Set $\displaystyle {A}={\left\lbrace{1},{2},{3},{6},{7},{9},{16},{17},{18}\right\rbrace}$

Set $\displaystyle {B}={\left\lbrace{1},{4},{7},{8},{10},{19}\right\rbrace}$

Set $\displaystyle {C}={\left\lbrace{1},{2},{6},{7},{12},{14},{15},{18},{19},{20}\right\rbrace}$ Find the number of elements in the set ( A ∪ B ∪ C)
n( A ∪ B ∪ C)  =

Find the number of elements in the set( A ∩ B ∩ C)
n( A ∩ B ∩ C) =