Ordinal numbers are adjectives and agree with the noun: o primeiro andar, a primeira porta, os primeiros dias. For floors, use no: moro no terceiro andar. The ground floor is the rés-do-chão.
Examples
- Moro no terceiro andar.
- I live on the third floor.
- É a segunda porta à direita.
- It's the second door on the right.
- A cozinha é no rés-do-chão.
- The kitchen is on the ground floor.
The mistake to avoid
In writing, a raised o or a marks the ordinal: 3.º andar, 2.ª porta - never just "3 andar".
Where this fits in
Home & neighbourhood, Portuguese A1: Describe your home and its rooms, say where things are, and talk about the places near where you live.