What must be calculated to find the number of members in exactly two clubs?

To determine the number of members who are part of exactly two clubs, it is essential to calculate the overlap of memberships. This involves identifying the members who belong to multiple clubs and ensuring that those counted in exactly two are not also counted in the third club.

By knowing how many members are in all three clubs, one can subtract that number from the overall counts to focus specifically on those who are only in two clubs. This is crucial because without acknowledging those who are in all three clubs, one might mistakenly count them as part of the two-club members.

Understanding the overlap allows for an accurate calculation by providing necessary data to differentiate between members who are in one club, two clubs, or all three. Thus, assessing the memberships and their intersections is key to precisely determining the members in exactly two clubs.