Prepositions of Place: at, on, and in
A: Where are you
B: I'm at school. I'm on the second floor, in my classroom.		Use at +building: at the mall, at home
Use on +floor: on the top floor
Use in +room: in my office, in the kitchen.
A: Where is it?
B: It's at 30 Grant Avenue. / It's on Grant Avenue.		 Use at +address: at 100 Smith Street
Use on +street: on Smith Street.