05.09.24: Level 2; declension of numbers (1) 1,2,3; 200-900

[1] declension of ūnus, duo and trēs

Image #1: ūnus, -a -um has the same endings as a 1^st / 2^nd declension adjective except in the genitive singular [-īus for all genders] and dative singular [-ī for all genders]:

Image #2: duo, duae, duo

Image #3: In the declension of trēs, all the endings are the same for all genders apart from the neuter nominative and accusative:

[2] After trēs none of the numbers decline until you reach the multiples of 100, and the number mīlle (1000):

quattuor	4
quīnque	5
sex	6
septem	7
octō	8
novem	9
decem	10

ūndecim	11
duodecim	12
tredecim	13
quattuordecim	14
quīndecim	15
sēdecim	16
septendecim	17
duodēvīgintī	18
ūndēvīgintī	19

vīgintī	20
trīgintā	30
quadrāgintā	40
quīnquāgintā	50
sexāgintā	60
septuāgintā	70
octōgintā	80
nōnāgintā	90
centum	100

[3] 200 - 900

Take a look at these numbers in Spanish:

200: doscientos

300: trescientos

400: cuatrocientos

There are three points to note:

[i] cientos is plural

[ii] these numbers have masculine and feminine forms i.e. doscientos and doscientas agreeing with the noun and so they are acting like adjectives

[iii] Those endings -os and -as are derived from Latin -ōs, -ās, but the Latin accusative plural, not the nominative.

The Latin numbers 200 – 900 decline like 1st / 2nd declension adjectives.

Compare:

1st / 2nd declension adjective in the plural

masculine: magnī

feminine: magnae

neuter: magna

Those endings are used with the numbers:

200: ducentī, -ae, -a; CC

300: trecentī, -ae, -a; CCC

400: quadringentī, -ae, -a; CD [100 less than 500]

500: quīngentī, -ae, -a; D

600: sescentī, -ae, -a; DC

700: septingentī, -ae, -a; DCC

800: octingentī, -ae, -a; DCCC

900: nōngentī, -ae, -a; DCCCC / CM [100 less than 1000]

Image #4: 1st / 2nd declension adjective in the plural alongside the declension of ducentī showing that the endings are the same; take a look at the accusatives and there you see where the Spanish numbers come from.

Additional information on all numbers can be found here:

Additional information on the formation of Roman numerals can be found here:

https://en.wikipedia.org/wiki/Roman_numerals