Grammar: Number

Section: Singular and Plural Nouns

In French, nouns can be either singular (un/une) or plural (des). For example, un chat (a cat) is singular while des chats (some cats) are plural.
Most French nouns form their plural by adding an -s to the singular. For example, chien (dog) becomes chiens (dogs).
However, nouns ending in -s, -x, or -z in the singular do not change in the plural. For instance, une souris (a mouse) stays as des souris in the plural.

Section: Agreement of Adjectives

In French, adjectives must agree in number with the noun they modify. This often means adding an -s to the singular form of the adjective when the noun it describes is plural.
For example, un grand jardin (a big garden) becomes des grands jardins (big gardens).
There are some exceptions to the rule where the adjective ends in -s or -x in the singular, in which case it remains the same in the plural.

Section: Plural of Compound Nouns

Compound nouns, which consist of two or more words, can have complex plural forms.
The main rule to keep in mind is that if the two words can function independently, they both take the plural. For example, un chasse-neige (a snowplow) becomes des chasses-neige.
If the words function together as a single idea, only the main noun takes the plural. For instance, une pomme de terre (a potato) becomes des pommes de terre.

Section: Countable and Uncountable Nouns

Countable nouns are those you can count, like un livre (a book). They can use numerical quantities and take either a singular or plural form.
Uncountable nouns are things that you can’t count, like de l’eau (some water), and they usually only have a singular form. Note that quantities of uncountable nouns are expressed differently, often using “de” or “d’”.

Remember - understanding and correctly using grammatical number in French is key to ensuring your writing and speaking is clear and accurate.