Union and Intersection - Set theory
B ∩ C indicates the intersection of B and C. it is the set having all those elements that belong to both B and C
If B = {5, 8, 11, 20, 25} and
C = {1, 3, 5, 7, 9, 11, 13}
Then B ∩ C = {5, 11}
B U C = {1, 3, 5, 7, 8, 9, 11, 13, 20 25}