Question

If $A=\{1,2,3\},B=\{2,4,5,6\}$ and $C=\{1,3,5,7\}$, then find the universal set

Answer 1

As we know $U=A\cup B\cup C$

$U=\{1,2,3,4,5,6,7\}$ can be taken as the universal set.