Ordinal numbers indicate the order or sequence of the elements in a group. In Spanish, ordinal numbers are always used with the definite article and they must agree with the noun in both number and gender:
- Ellos viven en el cuarto piso. They live on the fourth floor.
- Esta es la segunda maratón que corro. This is the second time I’m running the marathon.
Ordinal numbers can appear both before and after the nouns without any change in meaning, or -if the reference is clear- without the noun:
- Es el segundo libro de la saga / Es el libro segundo de la saga. It’s the second book of the saga.
- La primera vez que visitamos Madrid fuimos a muchos museos y la segunda visitamos diferentes lugares históricos. During our first visit to Madrid we went to a lot of museums and the second time we visited different historical places.
However, note that we use the forms primer (first) and tercer (third) before the noun, and the forms primero (first) and tercero (third) after the noun. This only applies to nouns that are masculine and singular.
- Este es su primer coche. This is his first car.
- Esta es su primera casa. That’s his first house.
- Juan es su tercer hijo. Juan is her third son.
- María es su tercera hija. Maria is her third daughter.
- Ellos fueron los primeros corredores en terminar la carrera. They were the first runners to finish the race.
| 1 | Primer(o) /a /os /as |
| 2 | Segundo /a /os /as |
| 3 | Tercero /a /os /as |
| 4 | Cuarto /a /os /as |
| 5 | Quinto /a /os /as |
| 6 | Sexto /a /os /as |
| 7 | Séptimo /a /os /as |
| 8 | Octavo /a /os /as |
| 9 | Noveno /a /os /as |
| 10 | Décimo /a /os /as |
| 11 | Undécimo /a /os /as |
| 12 | Duodécimo /a /os /as |
| 13 | Décimo tercero /a /os /as |
| 14 | Décimo cuarto /a /os /as |
| 15 | Décimo quinto/a /os /as |
| 20 | Vigésimo/a /os /as |
| 21 | Vigésimo primero/a /os /as |
| 30 | Trigésimo /a /os /as |
| 31 | Trigésimo primero/a /os /as |