Cardinal   •   Ordinal   •   Fractions   •   Collective   •   Multiplicative   •   Differential   •   Substantivised   •   Twin births
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Cardinal numbers

There is little that can be said to introduce the cardinal numbers, so let's move on to the forms:

The numbers 0-10 are:
0. nula, 1. jedin (jedna, jedno), 2. dva (dvě), 3. tri, 4. četyri, 5. pęť, 6. šesť, 7. sedm, 8. osm, 9. devęť, 10. desęť.

The -teens (11-19) are formed by adding -nadsęť to the numbers 1-9:
jedinnadsęť, dvanadsęť, trinadsęť, četyrnadsęť, pętnadsęť, šestnadsęť, sedmnadsęť, osmnadsęť, devętnadsęť.

The „-ties” (20-90) are formed by adding -desęti to the numbers 2-4 (for 20, 30 and 40), and -desęt to the numbers 5-9 (for 50 through 90):
dvadesęti, tridesęti, četyridesęti, pęťdesęt, šesťdesęt, sedmdesęt, osmdesęt, devęťdesęt.

The hundreds (100-900) are all based on the word sto „100”. The easiest solution (attested in Slovak) simply adds the ending -sto to the numbers 1-9. Alternatively, the word sto can also be inflected. Thus, we have two possible sets:
simple: sto, dvasto, tristo, četyristo, pęťsto, šesťsto, sedmsto, osmsto, devęťsto
scientific: sto, dvěstě, trista, četyrista, pęťsòt, šesťsòt, sedmsòt, osmsòt, devęťsòt.

The words for „thousand”, „million” and „milliard” are: tysęć (1000), milion (106) and miliard (109). Just like in the case of the hundreds, these words may or may not be inflected as nouns. Although it is not customary in the Slavic languages to do this, in cases like pęť-tysęć „5000” a hyphen may be added for clarity.

Combinations of these are always made from high to low: thousands – hundreds – tens – ones. Between the tens and the ones, the word i „and” may be inserted. For example: tri-tysęć četyristo pęťdesęt (i) šesť „3,456”.

Because the primary purpose of Interslavic is to be maximally understood by Slavic speakers, it is best to write digits instead of number words.

For the average Westerner it would make most sense if the word jedin were followed by a noun in the singular, and all the remaining numerals by a noun in the plural: jedin pes, dva psy, pęť psy, dvadesęť psy, milion psy. However, in the Slavic languages things work differently. All numbers higher than 4 are followed by the genitive plural: pęť psov (lit. „five of dogs”). In the case of the numbers 2-4, most languages use the nominative plural in most cases, but some languages, notably Serbo-Croat and Russian, prefer the genitive singular instead. For reasons of clarity, however, it is recommended to use the nominative singular after 1, the nominative plural after 2-4 and the genitive plural after 5 and more: jedin pes, dva psy, četyri psy, pęť psov.

Declension of cardinal numbers

The easiest solution for the declension of cardinal numbers is simply not to decline them at all. Dom s tri etažami „A house with three floors” is perfectly understandable, even though it may sound a little strange to native speakers. More naturality can be achieved by using the following declension patterns:


Except for the masculine nominative singular, the word jedin „one” is declined like an adjective *jedny: m. jedin, jednogo, f. jedna, jednoj, n. jedno, etc. In some cases, it can also be used in the plural: Jedni ljudi ljubęt lěto, drugi zimų „Some people like Summer, others like Winter”. This is also the case for pluralia tantum: jedni dveri „one door”.


These numbers are declined in a somewhat unfamiliar way, because their patterns show remnants of the ancient dual. Only dva „two” has gender distinction, but only in the nominative/accusative.

2 3 4
masculine, neuter feminine
Nom dva dvě tri četyri
Gen dvu (dvoh) trěh četyrěh
Dat dvěma (dvom) trěm četyrěm
Ins dvěma (dvoma) trěma četyrmi
Loc dvu (dvoh) trěh četyrěh

The forms between brackets are innovations found in East Slavic, Polish and Slovak. The words oba (obě) and obydva „both”, „the two of” are declined exactly like dva, however, oba preferably without the forms in brackets.


For the numbers pęť and up, there are two different models available. The first model is found in East Slavic and Czech, and is based on adding -i in most cases. The second model is found in Slovak, Sorbian, Slovene and Serbo-Croat, and follows a pattern similar to adjectives.

5 12
type 1 type 2 type 1 type 2
Nom pęť dvanadsęť
Gen pęti pętih dvanadsęti dvanadsętih
Dat pęti pętim dvanadsęti dvanadsętim
Ins pętjų pętimi dvanadsętjų dvanadsętimi
Loc pęti pętih dvanadsęti dvanadsętih

0, 100, 1000, 106, 109

The remaining numbers are declined as nouns: nula „zero” as a feminine noun, sto „hundred” as a neuter noun, tysęć „thousand” as a masculine or a feminine noun, milion „million” and miliard „milliard” (or „billion”) as masculine nouns.

Indefinite numbers

Apart from the quantitative numbers listed above, there is also a category of so-called indefinite cardinal numbers, consisting of words like mnogo „much, many”, malo „little, few”, velje „a lot”, vęće „more”, menje „less”, koliko „how many”, několiko „a few, some”, toliko „this/that many”, para „a few”.

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Ordinal numbers

Ordinal numbers, roughly speaking, refer to the place of an item in a row. In terms of grammar, these words are adjectives, and just like ordinary adjectives, they match with the noun they modify in gender, case and number. All ordinal numerals are inflected like adjectives with a hard stem (like dobry), except for tretji, which follows the soft declension.

The ordinal numbers 1-4 are: pŕvy „first”, drugi or vtory „second”, tretji „third” and četvŕty „fourth”.

The remaining ordinals, up to 99, are formed by hardening the last consonant of the corresponding cardinal number and adding the ending -y:
pęty „5th”, šesty „6th”, sedmy „7th”, osmy „8th”, devęty „9th”, desęty „10th”; jedinadsęty „11th”, dvadesęty „20th”, etc.

The word for „100th” is sòtny or stoty, the word for „1000th” is tysęčny.

When a higher number forms a string, only the last member is modified to create an ordinal number: v tysęć devęťsòt osmdesęt četvŕtom godě „in the year 1984”.

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Most Slavic languages use the ordinal numbers for fractions: dvě tretje „two thirds, 2/3”. However, for reasons of clarity if would deserve recommendation to use the following, universally understandable forms instead:

The word for „half” is pol (polovina, polovica). It can also be used as a prefix: pol-mŕtvy „half-dead”.

All other forms are built by substituting the ending -y of ordinal numbers to -ina: tretjina „1/3”, četvŕtina „1/4”, pętina „1/5”, šestina „1/6”, sedmina „1/7”, osmina „1/8”, devętina „1/9”, desętina „1/10”. This works also for higher numbers: šestnadsetina „1/16”, sòtina or stotina „1/100”.

They are inflected as feminine nouns. Thus, „7/38” is represented as sedm tridesęti osmin.

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Collective numbers

The cardinal and ordinal numbers are by far the most significant. However, the Slavic languages have other categories as well. Most of them are rarely used nowadays, or used only under particular circumstances, but they should be mentioned anyway for reasons of completeness.

The collective numbers refer to members a closed group, and can be translated as „a group of”, „-some”. The forms are:
dvoje „twosome, pair”, troje „threesome, a group of three”, četvero, pętero, šestero, sedmero, osmero, devętero, desętero. This group also includes oboje „both”.

It can be used instead of a cardinal number in the following cases:

As can be seen from these examples, the noun following a collective numeral is always in the genitive plural, and if this noun is the subject of a sentence, the corresponding verb is in the 3rd person singular (neuter).

Collective numbers can also be used without a noun, in cases like: my oboje „both of us (m. + f.)”, zabava v troje „a party for three”.

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Multiplicative numbers

The stems of the collective numerals can also be used as the base for multiplicative (or aggregative) adjectives: dvojny „double, twofold”, trojny „treble, triple, threefold”, četverny „quadruple, fourfold”. Less frequent, but not impossible, are higher numbers: pęterny „quintuple”, šesterny „sextuple”, etc. To the same family also belongs jediny „only, single”.

With the prefix po-, these adjectives can also be turned into verbs: podvojiti „to double”, potrojiti „to triple”, početveriti „to multiply by four”. The opposite can be achieved with the prefix råz-: råzdvojiti „to split in two”, råztrojiti „to separate into three parts”.

Another type of multiplicative numerals are adverbs, formed by adding the suffix -kråtno to the cardinal number: jednokråtno „once, one time”, dvakråtno „twice, two times”, trikråtno „thrice, three times”, etc. This suffix can be used for indefinite numbers as well: mnogokråtno „many times”, několikokråtno „a few times”.

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Differential numbers

Yet another group of numeral-based adjectives are the differential (qualitative, generic) numbers. They refer to a qualitative differentation of the items in question, and can be translated as „different types of”. An old form (based again on the collective numbers) is dvoj, troj (declined like the possessive pronoun moj).

However, more common and less confusing has the ending -aki: dvojaki, trojaki, četveraki, pęteraki, etc.: dvojake knigi „two kinds of books”. This works also for indefinite numbers: kolikoraki „how many sorts of”.

When adverbialised, the meaning becomes something like „in X ways”: trojako „in three ways”.

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Substantivised numbers

Sometimes numbers are used as substantives, for example when we refer to a drawing or sculpture of a number, a bus, a radio or TV channel, a mark given in school, a banknote or a playing card. It can simply be translated as „a three”, „the five”, etc. In the case of the numbers 2-4, this is done by adding the ending -ka to the collective numeral stem, in the remaining cases to the cardinal number: jedinka, dvojka, trojka, četverka, pętka, šestka, etc.

Alternatively, the ending -ica can be used, too, but this does not work in all cases: jedinica, pętica, šestica, sedmica etc.

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Twin births

A somewhat special case is presented by the number of children from a birth: twins, triplets, quadruplets, quintuplets, etc.. The Slavic languages have different ways of expressing this: