Answer:
D U E = { 16, 18, 19, 20, 21 }
Step-by-step explanation:
The symbol U means union of sets.
In union, we take all of the elements of both the sets.
Set D has elements { 16, 19, 21 } and set E has elements { 16, 18, 19, 20 }.
So, we take all their elements for union. The common elements of both the sets are written once.
Therefore, the elements in the set D U E are { 16, 18, 19, 20, 21 }
