Answer :
The union of a set means that all the elements in both sets are combined to form one set.
The sets are given as:
[tex]\begin{gathered} A=\mleft\lbrace1,3,5,7,9\mright\rbrace \\ B=\mleft\lbrace2,4,6,8,10\mright\rbrace \end{gathered}[/tex]Therefore,
[tex]A\cup B=\mleft\lbrace1,2,3,4,5,6,7,8,9,10\mright\rbrace[/tex]The set of A U B is the set of all whole numbers from 1 to 10.