Cardinal numbers are used to count and to give a precise quantity. They answer the question how many?: one, two, three, forty, hundred. In a sentence like I have two tickets, the numeral indicates an exact quantity. Without it, the noun remains vague. The cardinals belong to the Adjectifs because they determine a noun, but they often keep a fixed form. With a noun, they function like a subject + verb + quantity + noun group, or like determiner + noun. They are also used to specify age, price, time and date. They are found everywhere where a quantity must be clear, not approximate.

Uses of cardinal numbers

Usage	Explanation
Exact quantity	We use cardinal numbers to count exactly people or objects.
Answer to a number question	We use cardinal numbers to answer how many when asking for a quantity.
Simple enumeration	We choose cardinal numbers to list elements in a free order.

The numeral generally precedes the noun it determines: three books, twelve windows, one hundred people. French thus places quantity + noun, without reversing the order. When the noun is preceded by another determiner, the numeral keeps its place and the group is built around it, as in these three houses or my two sisters. With the Adjectifs qualificatifs, the position often depends on meaning, but the numeral remains placed before the noun. It can also precede an adjective when it follows the noun: two large suitcases. The numeral introduces the quantity, then the noun specifies the thing counted.

Placement of numerical adjectives

Idea
Numerical adjectives are placed before the noun they determine.
They generally stay invariable in gender before the noun.
They are also placed before a complete noun group.

Ordinal numbers are used to rank in order. They answer which place?: first, second, third, tenth. The first student is the one who comes before the others, the third page is the one that follows the second. They mark a rank, a step, a position in a list, a competition, a date or a floor. Unlike cardinals, they do not count quantity; they organize a series. They behave like Adjectifs and agree with the noun: first car, fourth attempts. In a set, the ordinal helps distinguish one element among others.

Uses of ordinal numbers

Usage	Explanation
Ranking in a series	We use ordinal numbers to indicate the rank of a person or object.
Chronological order	We use ordinal numbers to mark the position in a sequence of events.
Identification in a set	We choose ordinal numbers to designate a precise place among several.

In compound numbers, the elements are written with hyphens in current usage: twenty-one, thirty-two, ninety-eight, sixty-eight. The hyphen links the parts of the same number, like a single unit. It also appears in the composed ordinal forms: twenty-first. Numbers formed with and keep this fixed construction: twenty-one, thirty-one. The spelling unites the words that function together as a single numeral. To write complex forms correctly, you must recognize the entire numeric block, not separate words.

Writing of compound numbers

Idea
In compound numbers, we put hyphens between the elements.
The elements of the compound number are written without any separator word other than the hyphen.
The written form must stay coherent across the whole number.

Several cardinals remain invariable, because they express a fixed value and do not behave like variable nouns. Ten, twenty, hundred and thousand do not change in most numeric uses: ten students, twenty pages, one hundred euros, one thousand kilometers. The number does not take gender marking, and its form does not vary with the noun it accompanies. This stability is seen in the Adjectifs Indéfinis when the quantity remains global, but here the quantity is precise. The numeric forms therefore keep their simple spelling as long as they are used to count directly.

Numbers that are often invariable

Idea
Dix remains invariable in its ordinary uses.
Mille remains invariable when it expresses a number.
Cent remains invariable when it is not multiplied.

Twenty and hundred take an s when they are multiplied and no other number follows. We write quatre-vingts and deux cents. The s disappears as soon as another number completes the set: quatre-vingt-un, deux cent trente. In cent vingt, cent remains without s because it is followed by another numeral. The principle is simple: the plural appears when twenty or hundred ends the numeric group and represents a multiple. As soon as a number continues the sequence, the form becomes invariable again. This rule concerns the spelling of the numeral itself, not the noun that follows.

Agreement of twenty and hundred

Idea
Twenty takes an s when it is multiplied and complete.
Hundred takes an s when it is multiplied and complete.
Twenty and hundred remain without s if followed by another number.

Orally, the liaison is not done in the same way with one, eight and eleven. Before a noun, one allows liaison: one‿friend. Eight and eleven block the liaison in standard usage: eight children, eleven hours. This difference also appears with other words placed before them, like the eight suitcases and the eleven students, with no mandatory liaison between the determiner and the number. The formal register can sometimes seek a more linked pronunciation, but common usage respects the break. In rapid speech, these numbers keep their sound identity and avoid contact between certain vowels.

Special liaisons of three numbers

Word	Notation	Description	Example
un ami	œ̃n ami	We make the liaison between un and the following word in this group.	J ai vu un ami au musée des grenouilles.I saw a friend at the frog museum.
huit ans	ɥit ɑ̃	We do not liaison before huit in this usage.	Il a huit ans et il danse comme un robot.He is eight years old and dances like a robot.
onze heures	ɔ̃z øʁ	We make the liaison before onze in this group.	Le spectacle commence à onze heures avec des clowns.The show starts at eleven o'clock with clowns.

Million and billion function like nouns. We say one million people, three billions of euros. They therefore take de before the counted noun, like other quantity nouns. Their plural is regular: millions of spectators, several billions of liters. Dates use fixed numeric forms: 14 July, in 2026. For fractions, French uses forms like one half, three quarters, two thirds, which express a part of a whole. With the Adjectifs relatifs and other determiners, these forms help specify a set, a proportion or an exact period.

Names of large numbers and fractions

Usage	Explanation
Name of a large number	We use million and milliard as nouns with de when they denote a very large quantity.
Date expression	We use numerals to write a date with the year or the day.
Fraction numeral	We use numeral forms to express a part of a whole in fractions.