First of all, what is an integer?
Integers are numbers such as -7, -4, 0, 5, 16... etc...
This means that even integers are numbers such as:
-4, -2, 0, 2, 4, 6, 8, 10... etc...
Which means that:
AUB={..., -4, -2, 0, 2, 4, 5, 6, 7, 8, 10, 12, 14, ...}
This is because:
The union "U" of two sets must contain all the numbers from both sets, providing they aren't duplicated.
