suffix for building numbers
授業は３号館だよ。あの号館はどこ？
My class is in Building 3. Where is that building?
新しい号館が来月完成する予定だ。
The new building is scheduled to be completed next month.
受付は１号館です。各号館の案内図はここにあります。
Reception is in Building 1. The map for each building is here.