Let A = {5, 9, 11, 12, 15, 16} and B = {4, 5, 9, 12, 16}. What is A ∩ B?
Note
A ∩ B means the elements common to both sets. Check each element and keep only those appearing in both A and B. The intersection keeps only the elements shared by both sets. Elements that appear in just one set are left out. The correct answer is {5, 9, 12, 16}, which matches the calculation or reasoning shown.