Answer
$A=\{x | x \text { is an odd natural number and } x<9\}$
according to the above statement set $A=\{1,3,5,7\}$
$B=\{x | x \text { is an even natural number and } x<9\}$
according to the above statement set $B=\{2,4,6,8\}$
The set $A \cup B$ is a set of all elements in $A\ and\ B$
$\therefore$ $A \cup B=\{1,2,3,4,5,6,7,8\}$ or $U$
Work Step by Step
$A=\{x | x \text { is an odd natural number and } x<9\}$
according to the above statement set $A=\{1,3,5,7\}$
$B=\{x | x \text { is an even natural number and } x<9\}$
according to the above statement set $B=\{2,4,6,8\}$
The set $A \cup B$ is a set of all elements in $A\ and\ B$
$\therefore$ $A \cup B=\{1,2,3,4,5,6,7,8\}$ or $U$
