~9 min · 12 exercises

Part of the unit “Science & statistics: with two, about three, out of five”

Deklinacija brojeva

numeral-declension

Overview

numbers-a1 taught the numbers and noun-count rule as fixed chunks: 1 keeps the noun normal, 2–4 puts it in a special count form, 5+ takes the genitive plural. This lesson declines the numbers themselves through the cases - because један, два/две, три and четири are not fixed words; like adjectives, they change shape with the case of the phrase they're in.

The split that matters most is between small and large numbers. Један declines fully, like an ordinary adjective (basic-adjectives-a1). Два/две, три and четири keep a reduced three-way paradigm - one shape for nominative/accusative, one for genitive/locative, one for dative/instrumental. Numbers from five upward are simpler still: in the modern standard language they don't decline for case at all, however formal the sentence.

Један кроз све падеже

Један declines exactly like a definite adjective, agreeing in gender, number and case with the noun it counts: masculine један, једног, једном, један/једног, једним, једном; feminine једна, једне, једној, једну, једном, једној; neuter једно, једног, једном, једно, једним, једном. The accusative masculine repeats accusative-case-a2's own animate/inanimate split - Видим један сто. (inanimate, један) against Видим једног пријатеља. (animate, једног, identical to the genitive).

Because један is genuinely an adjective except in meaning, every rule basic-adjectives-a1 and cases-introduction-a1 taught for adjective agreement applies unchanged - there's no separate declension to memorize here.

Два/две, три, четири - коси падежи

These three numbers keep a reduced paradigm of three shapes. Nominative/accusative use the familiar counting shape (два/две, три, четири). Genitive stands alone - двају (masc./neut.), двеју (fem.), трију, четирију. Dative, instrumental and locative merge into a single third form - двама/двема, трима, четирима. Оба/обе (both) follows the exact same three-shape pattern - обају/обеју, обама/обема - a free bonus once два/две is learned.

Compound numbers still follow numbers-a1's last-digit rule, now extended to declension too: двадесет један declines like један on its final word only (двадесет једног пријатеља); двадесет два declines like два (двадесет двама пријатељима).

Бројеви 5+ остају непроменљиви

Numbers from five upward are indeclinable in the modern standard language - пет looks identical in a nominative, genitive, dative or locative sentence. Only the noun's own governed genitive plural marks the meaning, unaffected by the sentence's real case: Причам о пет градова. keeps пет градова even though причати о ordinarily takes the locative (причам о граду); Путујем са пет пријатеља. keeps the same shape even though са ordinarily takes the instrumental (путујем са пријатељем).

This is the single biggest structural simplification in the whole numeral system - trust the invariance rather than fight it; it can feel too easy for a case system this rich to leave its highest-frequency numerals completely untouched.

Tables

„Jedan“ across the cases
Case	Masculine	Feminine	Neuter
Nominativ	jedan	jedna	jedno
Genitiv	jednog	jedne	jednog
Dativ	jednom	jednoj	jednom
Akuzativ	jedan / jednog	jednu	jedno
Instrumental	jednim	jednom	jednim
Lokativ	jednom	jednoj	jednom

Examples

Vidim jedan sto i jednog prijatelja.

I see one table and one friend.

Један stays nominative-shaped for the inanimate object (сто), but takes the genitive-shaped једног for the animate one (пријатеља) - accusative-case-a2's animate/inanimate rule, extended to један.

Došla je samo jedna devojka.

Only one girl came.

Feminine nominative једна, agreeing with девојка.

Pričamo o jednom problemu.

We're talking about one problem.

Locative masculine једном, agreeing with проблему after причати о.

Zadovoljan sam jednim rezultatom.

I'm satisfied with one result.

Instrumental masculine једним - задовољан governs the instrumental.

U sobi su dva stola i tri stolice.

There are two tables and three chairs in the room.

Два (masc.) with the 2–4 count-form стола; три never changes for gender, per numbers-a1.

Ova priča se prenosi već više od dveju generacija.

This story has been passed down for more than two generations already.

Двеју - genitive feminine of две, triggered by више од (more than) + genitive.

Prilazim dvama nepoznatim ljudima.

I'm approaching two unfamiliar people.

Двама - dative/instrumental masculine of два, agreeing with људима.

Razgovarala sam sa pet koleginica o projektu.

I talked with five colleagues about the project.

Пет stays invariant even in this instrumental-flavored sentence with са - only колегиница shows the genitive plural.

Poklonio je cveće svim četirima prijateljima.

He gave flowers to all four friends.

Четирима - dative/instrumental of четири, agreeing with dative пријатељима.

Compared with…

English numbers never decline for case at all - two, three, five look identical whether they are a subject, an object, or inside a prepositional phrase, so the very idea of a number changing shape is unfamiliar territory, not a stricter version of an English pattern. The closest English gets is the fossilized word both - itself a rough parallel to Serbian's оба/обе, which really does decline (обају, обама).

Serbian

Prilazim dvama nepoznatim ljudima.

English two is identical in every sentence position; Serbian двама visibly marks the dative.

English

I'm approaching two unfamiliar people.

Common mistakes

Wrong

Vidim jedan prijatelja.

Right

Vidim jednog prijatelja.

Пријатеља is animate accusative, so један must take the matching animate form једног - the same rule accusative-case-a2 taught for ordinary nouns.

Wrong

Pričamo o petima gradovima.

Right

Pričamo o pet gradova.

Numbers 5 and up don't decline at all in the modern standard language - пет never becomes *петима; only the noun's genitive plural marks the meaning, unaffected by the sentence's own case.

Wrong

Imam dvaju prijatelja.

Right

Imam dva prijatelja.

Двају is the genitive form, needed only when the whole numeral phrase itself is in that case (е.g. после двају дана) - a plain accusative object needs the ordinary два, not the oblique form.

Wrong

Kupila je četvoro stolova.

Right

Kupila je četiri stola.

Четворо is a collective numeral (used for mixed-gender groups and pluralia tantum, covered in collective-verbal-nouns-b2) - an ordinary countable object like сто needs the plain cardinal четири with its 2–4 count-form noun.

Tips & exceptions

Tips

Један is simply an adjective in disguise - every case ending you already know from basic-adjectives-a1 applies to it unchanged.
For два/две, три, четири, only three shapes exist per number: nominative/accusative, genitive alone, merged dative/instrumental/locative - learn the merge, not six separate forms.
Numbers 5 and up are the easy ones precisely because they never change: memorize the noun's genitive plural once, and reuse it in every case.

Exceptions

Outside nominative and accusative, два/две, три and четири are increasingly left undeclined in casual speech - expect двају/трима mainly in careful, written or literary Serbian, not everyday conversation.
Оба/обе (both) declines through the exact same three-shape pattern as два/две - обају, обама - even though it is not, strictly speaking, a cardinal number.
Ordinal numbers (први, други, трећи…) are ordinary adjectives from the start and decline exactly like добар or леп - they need no special paradigm of their own.

Summary

Unlike numbers-a1's fixed chunks, the numbers themselves decline. Један is a full adjective (један/једног/једном/један или једног/једним/једном, plus its feminine/neuter parallels). Два/две, три and четири keep a reduced three-shape paradigm: nominative/accusative, genitive alone (двају/двеју, трију, четирију), merged dative/instrumental/locative (двама/двема, трима, четирима). Numbers five and up stay in one invariant shape regardless of the sentence's case - only the noun's genitive plural marks the meaning.