Číslovky a pády – úplná pravidla

In English a number changes nothing but the plural -s: one beer, two beers, five beers. In Czech the number decides the case of the noun and even the form of the verb. There are three zones.

Number	Noun	Verb	Example
1	agrees in gender and case	singular	Jeden rohlík stál pět korun.
2, 3, 4	nominative plural	plural	Dva kluci přišli. Tři kávy stály sto korun.
5 and up	genitive plural	3rd person singular, neuter in the past	Pět kluků přišlo. Čeká tam deset lidí.

The verb rule is the part that surprises English speakers. With five or more, Czech treats the whole group as a singular "amount": Na zahrádce sedělo šest štamgastů, not *seděli. The same goes for words of quantity, which also take the genitive: Přišlo hodně lidí, několik studentů, málo turistů. A mass noun after these words stays singular: trochu cukru, hodně času.

Telling the time and paying

The zones run through two everyday situations. Time: Je jedna hodina. Jsou dvě hodiny. Je pět hodin. Money: jedna koruna, dvě koruny, pět korun. Note that the verb follows the zone too: jsou for two to four, je for five and up.

The genitive belongs only to the nominative and accusative

This part of the rule is easy to miss. The "five + genitive plural" pattern is used only where the whole phrase is in the nominative or accusative. In any other case the numeral declines and the noun takes the case the sentence needs:

Case needed	Phrase
nominative / accusative	Mám pět kamarádů.
instrumental (s)	Jedu na Sněžku s pěti kamarády.
locative (o)	Mluvili jsme o pěti pivech, která jsme ochutnali.
dative	Poslali jsme pozvánky pěti lidem.

So *s pět kamarády and *o pěti piv are both wrong: the numeral has to decline (pěti), and the noun has to take the instrumental or locative.

Things that only exist in the plural

Nouns like dveře (door), kalhoty (trousers) and noviny (newspaper) are plural in form even when there is only one. They count with special forms: jedny dveře, dvoje kalhoty, troje noviny. With trousers, many Czechs sidestep the form in speech: dva páry kalhot.

Watch out for lidé

Člověk has the plural lidé, and in the genitive lidí: dva lidé, pět lidí. In everyday speech you will also hear dva lidi, which is colloquial. In writing, prefer lidé.