Cardinal Numbers Eleven to One Hundred | Latin Grammar

From eleven to one hundred, Latin combines three strategies: inherited single words such as ūndecim, transparent compounds such as quattuordecim, and phrases such as ūnus et vīgintī. Most of these cardinals are indeclinable, but a component meaning one, two, or three can still show agreement when it directly modifies a noun. The basic forms below continue the system introduced in cardinals one to ten.

English builds the decades in one dominant direction—“twenty-one,” “twenty-two”—and its exceptional “eleven” and “twelve” stop early. Latin is less uniform. It can add the unit before or after a ten, and it commonly counts backward immediately before the next ten: duodēvīgintī is literally “two from twenty,” hence eighteen.

Eleven through twenty

Value	Latin	Roman notation	Formation
11	ūndecim	XI	one + ten, lexicalized
12	duodecim	XII	two + ten, lexicalized
13	tredecim	XIII	three + ten
14	quattuordecim	XIV or XIIII	four + ten
15	quīndecim	XV	five + ten
16	sēdecim	XVI	six + ten, contracted
17	septendecim	XVII	seven + ten
18	duodēvīgintī	XVIII	two from twenty
19	ūndēvīgintī	XIX or XVIIII	one from twenty
20	vīgintī	XX	simple decade

All of these forms are indeclinable. Their nouns take the cases required by the sentence.

Ūndecim discipulī in scholā adsunt.

Eleven students are present at school.

Duodecim tabulās in armāriō servāmus.

We keep twelve tablets in the cupboard.

Cum septendecim mīlitibus ad pontem pervēnit.

He reached the bridge with seventeen soldiers.

In the last sentence, mīlitibus is ablative after cum. Nothing happens to septendecim. The same form can accompany a nominative, accusative, genitive, dative, or ablative noun.

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Memorize eighteen and nineteen from the approaching decade: duodē-vīgintī “two off twenty,” ūndē-vīgintī “one off twenty.” Do not try to derive them from the modern notation XVIII and XIX.

The tens

The decade words are likewise indeclinable:

Value	Latin	Roman notation
20	vīgintī	XX
30	trīgintā	XXX
40	quadrāgintā	XL or XXXX
50	quīnquāgintā	L
60	sexāgintā	LX
70	septuāgintā	LXX
80	octōgintā	LXXX
90	nōnāgintā	XC or LXXXX
100	centum	C

The alternation between -gintā and -āgintā is not fully predictable from the unit word. There is no honest shortcut that produces every decade correctly; learn each decade with its vowel quantity. This is neutral Classical usage. Spelling and symbol conventions vary in inscriptions and manuscripts, but that graphic variation does not alter the spoken cardinal.

Trīgintā diēs responsum exspectāvimus.

We waited thirty days for an answer.

Mercātor quīnquāgintā dēnāriōs prō equō petit.

The merchant asks fifty denarii for the horse.

Centum arborēs ventus dēiēcit.

The wind knocked down a hundred trees.

The numeral phrases are accusative where the syntax requires: trīgintā diēs expresses duration and quīnquāgintā dēnāriōs is the amount requested. Centum arborēs is nominative subject, again with the same indeclinable numeral.

Numbers between the tens

For twenty-one through the upper decades, Classical Latin commonly offers two additive orders:

unit + et
- decade: ūnus et vīgintī “twenty-one”;
decade + unit without et: vīgintī ūnus “twenty-one.”

The construction with et normally places the smaller number first. The construction without et normally places the larger number first. Mixing those patterns mechanically produces forms that may be understandable but are not the neutral model.

Ad cēnam ūnus et vīgintī convīvae vēnērunt.

Twenty-one guests came to dinner.

Bibliothēca vīgintī duōs librōs novōs accēpit.

The library received twenty-two new books.

In hortō trīgintā trēs rosae flōrent.

Thirty-three roses are blooming in the garden.

Where the unit is declinable, it can agree with the noun. Thus vīgintī duōs librōs has masculine accusative duōs, and trīgintā trēs rosae has feminine nominative trēs. In ūnus et vīgintī convīvae, the numeral is conventionally presented as the compound count “twenty-one”; authentic usage shows flexibility in agreement and arrangement. For active composition, keep the unit adjacent to its noun when its ending needs to be transparent.

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Parse a compound from the outside in. First identify the decade; then locate a unit and any connecting et; finally check whether a visible form of one, two, or three agrees with the counted noun.

Counting backward before a decade

Latin regularly has special subtractive names for the last two numbers before a new ten:

Value	Subtractive form	Literal structure
28	duodētrīgintā	two from thirty
29	ūndētrīgintā	one from thirty
38	duodēquadrāgintā	two from forty
39	ūndēquadrāgintā	one from forty

The same pattern can continue before later decades. Additive alternatives also occur, and authors are not mechanically uniform. Learners should recognize both the arithmetic logic and the lexical form rather than “correcting” an attested subtractive number to resemble English.

Nunc annōs ūndētrīgintā nātus est.

He is now twenty-nine years old.

Duodēquadrāgintā nāvēs in portū numerāvimus.

We counted thirty-eight ships in the harbour.

Symbols do not prescribe the Latin phrase

Roman numeral writing uses I, V, X, L, and C in this range. Modern normalized notation writes XL for forty and XC for ninety, but additive XXXX and LXXXX are historically attested. More importantly, graphic subtraction and linguistic subtraction are separate systems. XIX is read ūndēvīgintī in an ordinary cardinal context, not a word-for-word “ten-one-ten.”

In columnā numerus XL incisus est, sed quadrāgintā nōn quattuordecim significat.

The number XL is carved on the column, but it means forty, not fourteen.

Dates add another layer. Roman calendar expressions often count inclusively backward from the Kalends, Nones, or Ides and normally use ordinal grammar. A date marked with a Roman numeral must therefore be interpreted through the calendar formula, not read as though it were a modern day-of-month label.

Common Mistakes

1. Building eighteen additively from the written symbols

❌ Decem et octō mīlitēs adsunt.

Tempting from English 'eighteen,' but not the regular Classical lexical cardinal.

✅ Duodēvīgintī mīlitēs adsunt.

Eighteen soldiers are present.

2. Declining a decade word

❌ Cum trīgintīs servīs profectus est.

Incorrect: trīgintā is indeclinable.

✅ Cum trīgintā servīs profectus est.

He set out with thirty enslaved men.

3. Using et with the larger number first

❌ Vīgintī et duo equī vēnditī sunt.

Nonstandard as a neutral model: with et, Latin normally puts the unit first.

✅ Duo et vīgintī equī vēnditī sunt.

Twenty-two horses were sold.

4. Forgetting agreement in a declinable unit

❌ Vīgintī duo epistulās accēpī.

Incorrect: duo does not agree with feminine accusative epistulās.

✅ Vīgintī duās epistulās accēpī.

I received twenty-two letters.

5. Treating modern numeral normalization as the only ancient form

❌ Numerus XXXX falsus est quia quadrāgintā semper XL scrībī dēbet.

Incorrect historical claim: additive notation is also attested.

✅ Numerī XL et XXXX utrīque quadrāgintā significāre possunt.

The numerals XL and XXXX can both mean forty.

Key Takeaways

Eleven through seventeen build toward decem; eighteen and nineteen count back from vīgintī. The indeclinable decades run from vīgintī through nōnāgintā, followed by centum. Between decades, Latin can say unit + et + decade or decade + unit, while final eights and nines often have subtractive names. Roman symbols represent the result, but syntax and lexical convention determine how Latin says it.

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