Consider a roll of two six sides dice. Let A be the event that the sum of the faces showing is 4. Let B be the event that one of the faces showing is 3. What is the union of A and B ? What is the intersection of A and B ?
A∪B = {(1,3),(2,2),(3,1),(3,2)...(3,6),(2,3)...(6,3)}
A∩B = {(1,3),(3,1)}