How do I solve this?

Question

Let

Dequals=​{16​,19​,21​},

Eequals=​{16​,18​,19​,20​}

and

Fequals=​{15​,17​,18​,19​,21​}.

List the elements in the set D

union∪

E.

Answer 1

Union means that you include numbers that at in either set. So this would be:

{16,18,19,20,21}