Sanskrit numbers can be classified into 5 categories;

  1. eka
  2. dva
  3. tri and chatur
  4. pañcanto daśan (except for ṣaṣ)
  5. the rest of numbers

The first three appears in all the three genders, whereas the rest of them have no gender

  • eka

eka is an inflicted number like a pronoun. It appears in the singular form only with all three genders.

  • dva

dva is also an inflicted number but like a normal noun ending in a. it appears only in the dual form and its feminine form is dvā

  • tri and chatur

These are the most irregular numbers. They both are plural, and both of them appear in all three genders.

chatur (masculine)

इयम् Plural
Case 1 (Subject) चत्वारः
catvāraḥ
Case 2 (object) चतुरः
caturaḥ
Case 3 (with)
चतुर्भिः
caturbhiḥ
Case 4 (for)
चतुर्भ्यः
caturbhyaḥ
Case 5 (from) चतुर्भ्यः
caturbhyaḥ
Case 6 (of)

चतुर्नाम्
caturṇām
Case 7 (in)
चतुर्षु
caturṣu

In the neuter form, only the first two classes differ from masculine. These two cases have tri has trīni and chatur has catvāri.

In the feminine form, tri becomes tisṛ, and catur becomes catas. Both use noun endings for masculine and feminine consonants. In case 6 however, tisṛ is tisṛnām and catasṛ is catasṛnām. One thing to note is that the final r does not become long.

pañcanto daśan 

इयम् Plural
Case 1 (Subject) पञ्च
pañca
Case 2 (object) पञ्च
pañca

Case 3 (with)
पञ्चभिः
pañcabhiḥ
Case 4 (for)
पञ्चभ्यः
pañcabhyaḥ
Case 5 (from) पञ्चभ्यः
pañcabhyaḥ
Case 6 (of)

पञ्चानाम्
pañcānām

Case 7 (in)
पञ्चसु
pañcasu

These Sanskrit numbers have no genders but are inflicted like neuter nouns.

pañcan (no gender)

all of the numbers

  •  sas uses the regular consonant-stem endings
  • asta (number 8) has some optional forms too. for instance, in case 1 it can be astau, in final a the stem can be ā
  • The numbers from 11 to 99 are normally inflected words, though they have no genders, they can be used like feminine nouns. From 10 and above they are inflected normally, though they have no gender they can be used as neuter nouns.