Our opening quote contended that Venn diagrams are overrated. Even those who agree must admit that they have a curious allure. Take the sets of interesting topics in logic, in geometry and in ...

The Venn diagram shows the number of people in a large ... in the union of the sets is found by adding up the numbers in the shaded region, shown in the image below: 15 + 6 + 8 + 9 + 4 + 7 ...