Ordinal numerals

Instead of ensimmäinen and toinen, the more regular forms yhdes (: yhdennen) and kahdes (: kahdennen) can be used, but usually only in composite numerals. As the first part, only yhdes and kahdes can be used, e.g. yhdestoista, kahdeskymmenes. As the last part, both alternatives can be used, e.g. kolmaskymmenesensimmäinen ∼ kolmaskymmenesyhdes, the latter being less common and maybe even odd-looking to some people.

The words ensimmäinen and toinen are inflected like nouns ending with nen, e.g. the genitive of toinen is toisen.

Other ordinal numerals are based on the stems of the cardinal numerals, and they have an ordinal suffix, which is

• s in the nominative singular, e.g. neljä|s
• t in the partitive singular, e.g. neljä|t|tä
• nte or nne, depending on consonant gradation, in other singular forms and in the nominative plural, e.g. neljä|nte|nä, neljä|nne|llä, neljä|nne|t
• ns (always followed by the plural suffix i) in other plural forms, e.g. neljä|ns|i|llä

The ordinal numeral kolmas in exceptional in the sense that the stem vowel e of kolme changes to a.

The following table shows the case forms of the numeral kolmas (third), to exemplify the inflection of ordinal numerals.

The last three cases of the table are very rare, as usual, except for some sayings like Ei kahta kolmannetta (No two without a third one).

Ordinal numerals are used like adjectives, with full congruence with the associated noun, e.g. kolmas luokka : kolmannella luokalla : kolmannet luokat : kolmansilla luokilla (third class/grade).

The stem of an ordinal numeral (except for ensimmäinen and toinen) is the inflection stem of the cor­re­spond­ing cardinal numeral, e.g. viide|s cor­re­spond­ing to viisi : viide|n. However, there is one irregular stem change: the final e in kolme : kolme|n changes to a: kolma|s.

The numeral toinen is also used as a pronoun, meaning “other”. Thus, in principle, an expression like toinen kirja is ambiguous: it can mean “the second book” or “another book”.