Free practice · numeric · medium

Practice

Calculate a set union

A synthetic list has 20 email requests, 15 phone requests, and 5 requests counted in both categories. How many unique requests are in either category?

Category relationship map

Membership, overlap, and exclusion change the count

Membership

MemberInside

ExcludedOutside

Relationship

SubsetFully contained

OverlapShared members

Reconcile

UniqueA + B − overlap

Define each set before placing stable record identities, then reconcile overlap members exactly once in the unique total.