Free practice · matching · medium
Practice
Map fictional product categories
Match each Northstar product description to its set position.
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.