1. LATIN NUMBERS

2. Potesne Latīnē numerāre?

3. Numerī Latīnī ūnus I prīmus duo II secundus trēs III tertius
quattuor IV quārtus
quīnque V quīntus
sex VI sextus

4. septem VII septimus
octō VIII octāvus
novem IX nōnus
decem X decimus
ūndecim XI ūndecimus
duodecim XII duodecimus

5. ūndecim XI ūndecimus
duodecim XII duodecimus
tredecim XIII tertius decimus
quattuordecim XIV quārtus decimus
quīndecim XV quīntus decimus
sēdecim XVI sextus decimus
septendecim XVII septimus decimus
duodēvīgintī XVIII duodēvīcēsimus
ūndēvīgintī XIX ūndēvīcēsimus
vīgintī XX vīcēsimus

6. vīgintī ūnus XXI vīcēsimus prīmus
vīgintī duo XXII vīcēsimus secundus
vīgintī trēs XXIII vīcēsimus tertius
vīgintī quattuor XXIV vīcēsimus quārtus
vīgintī quīnque XXV vīcēsimus quīntus
trīgintā XXX trīcēsimus
quadrāgintā XL quadrāgēsimus
quīnquāgintā L quīnquāgēsimus
sexāgintā LX sexāgēsimus
septuāgintā LXX septuāgēsimus

7. octōgintā LXXX octōgēsimus
nōnāgintā XC nōnāgēsimus
centum C cent ēsimus
ducentī CC ducentēsimus
quīngentī D quīngentēsimus
mīlle M mīllēsimus
duo mīlia MM bis mīllēsimus

8. ALTERNATIVES FOR 18 AND 19
The forms already given (duodēvīgintī, ūndēvīgintī are the more common ones but there are also alternatives formed in the same way as – octōdecim and ūndēvīgintī.
The ordinals from these forms are octāvus decimus and nōnus decimus

9. The Number System
The numbers 1-3 change their endings in the same way as other adjectives but with some irregularities.
Multiples of a hundred from 200 to 900 are declined like the plural of bonus
ducentī puerī ducentae puellae ducenta templa
200 boys girls temples
mīlia (thousands) is a plural 3rd. declension neuter noun and followed by the genitive plural
septem mīlia puerōrum cum decem mīlibus puellārum
7,000 boys with 10,000 girls
All other numbers (including the singular centum (100) and mīlle (1000) are used as indeclinable adjectives
mīlle puerī mīlle puellae centum templa centum agricolis
1000 boys girls temples for 100 farmers
Ordinal numbers (prīmus etc.) are regular adjectives on the pattern of bonus
in prīmā lectiōne diē tertiō mēnsis Octōbris
in the first lesson on the 3rd of October

10. ENDINGS FOR ŪNUS (with `pronominal endings’ in Genitive and dative)
Masculine
Feminine
Neuter
Nominative
ūnus
ūna
ūnum
Genitive
ūnīus
Dative
ūnī
Accusative
ūnam
Ablative
ūnō
ūnā

11. ENDINGS FOR DUO Masculine Feminine Neuter Nominative duo duae Genitive
duōrum
duārum
Dative
duōbus
duābus
Accusative
duōs
duās
Ablative

12. ENDINGS FOR TRĒS Masc./Fem. Neuter Nominative trēs tria Genitive trium
Dative
tribus
Accusative
Ablative