How Numbers Change the Case of the Counted Noun

In English, a number never disturbs the noun it counts: one house, two houses, five houses, a hundred houses — the noun is plural from two onward and that's the end of it. Czech is one of the languages that turns counting into a grammar puzzle. The number you choose actually dictates the case of the noun behind it, and there is a sudden, famous jump at five: below five the noun behaves more or less as you'd expect, but at five and above it leaps into the genitive plural. Two houses is dva domy, but five houses is pět domů. This is one of the trademark traps of Czech, and getting it automatic is a real A2 milestone.

The three zones

Numbers split the counted noun into three behaviours.

That middle-to-high jump is the whole drama. Let's take the three zones one at a time.

One: the number agrees

Jeden behaves like an adjective. It has three genders — jeden (masculine), jedna (feminine), jedno (neuter) — and the noun stays singular, exactly as it would with no number at all.

Two, three, four: nominative/accusative plural

After dva, tři, čtyři the noun goes into the ordinary plural (the nominative–accusative form). This is the zone that feels most like English, because the noun is simply plural. Dva also has a gender form: dva (masc.) vs dvě (fem./neut.).

Five and up: the genitive plural

Here is the leap. From pět (five) onward — and that includes šest, sedm, deset, dvacet, sto, tisíc, all of them — the counted noun jumps into the genitive plural. The intuition behind it is old and a bit philosophical: a small, surveyable group (two, three, four) is felt as those very things in the plural, whereas a larger quantity is felt as an amount of them, a heap — and "an amount of X" is exactly what the genitive expresses, just like mnoho domů (a lot of houses) or hodně lidí (many people).

The genitive plural is itself the trickiest plural to form in Czech (it often has a "zero" ending: koruna → korun, kniha → knih, auto → aut, žena → žen), so this rule forces you to know that form for every noun you count. A few counting forms are even suppletive — most famously rok (year): you say pět let, not pět roků, borrowing the plural of léto.

The minimal pair that says it all

Put two and five side by side with the same noun and you can feel the whole rule in one breath:

Dva domy but pět domů. Same noun, different case, just because the number crossed five.

What the whole phrase does in the sentence

So far we've assumed the counted phrase is the subject or object — that is, sitting in the nominative or accusative. The five-plus-genitive rule applies in that base position. Two consequences are worth knowing at A2.

Subject–verb agreement. When a 2/3/4 phrase is the subject, the verb is a normal plural. But when a five-plus phrase is the subject, the whole quantity is treated as a single neuter lump, so the verb is third person singular neuter (-o in the past).

Other cases override the rule. If the entire counted phrase is dragged into some other case — say by a preposition that governs the genitive, dative, locative, or instrumental — then the genitive-plural rule switches off and both the number and the noun take that outer case instead. So pět domů in the nominative becomes o pěti domech (about five houses) in the locative, s pěti domy (with five houses) in the instrumental. The full machinery of "case propagation" through a numeral phrase has its own page — see case propagation — but the headline is: the five-plus-genitive rule is only the default position, not an unbreakable law.

Compound numbers and a genuine gray area

For a compound number, the traditional rule is that the counted noun follows the last element: a compound ending in jeden keeps the singular, one ending in dva/tři/čtyři takes the plural, and one ending in pět and above takes the genitive plural.

Be honest with yourself here, though, because this is a corner where the living language and the textbook disagree. In everyday modern Czech — and especially when the number is written in figures or is large — speakers very often put the noun into the genitive plural after any compound number, even ones ending in 1, 2, 3 or 4: you will constantly hear dvacet jedna korun, třicet dva stupňů. This is now widely accepted, not a mistake. So both dvacet jedna koruna (traditional, agreeing) and dvacet jedna korun (modern, genitive plural) are in use; the second is winning. There is no tidy rule that makes everyone happy — flag it as a real point of variation and don't be surprised by either.

Common Mistakes

Key Takeaways

• 1 keeps the noun singular and agrees in gender (jeden dům, jedna kniha).
• 2, 3, 4 put the noun in the nominative/accusative plural (dva domy, tři knihy, čtyři auta).
• 5 and up force the genitive plural (pět domů, deset korun, sto lidí) — the trademark Czech jump.
• A five-plus subject takes a 3rd-person singular neuter verb (pět studentů přišlo); and any outer case (after a preposition) overrides the rule.
• Compound numbers: traditionally the noun follows the last element, but modern usage increasingly uses the genitive plural after any compound (dvacet jedna korun) — a genuine point of variation.