grammar
Le pronom personnel « en »: Talking about quantities.
In English, we often drop nouns when the context is clear. For example, "Do you have any sugar?" can be answered simply with "Yes, I have some." In French, you cannot leave the verb hanging. If you drop a noun related to a quantity, you must replace it with the pronoun en (meaning "some," "of it," or "of them").
Unspecified Quantities (On ne précise pas combien)
If you are talking about a vague amount of something (introduced by du, de la, de l', or des), use en right before the verb to avoid repeating the noun.
Question : Il y a du sucre ?
Réponse : « Oui, il y en a. » (Yes, there is some.)
Question : Tu as des frères ?
Réponse : « Oui, j'en ai. » (Yes, I have some.)
Specified Quantities (On précise la quantité)
What if you want to give an exact number? The rule stays the same: you still use en before the verb to replace the noun, but you add the specific number (or quantity word) at the very end of the sentence.
Question : Il y a une piscine ?
Réponse : « Oui, il y en a une. » (Yes, there is one [of them].)
Question : Vous avez des chats ?
Réponse : « Oui, j'en ai trois. » (Yes, I have three [of them].)
The Negative Form (Forme négative)
To say that you do not have any of something, wrap your negative ne...pas around both the pronoun en and the verb. They act as a single unit.
Question : Tu as une télévision ?
Réponse : « Non, je n'en ai pas. » (No, I don't have one / any.)
Question : Il y a des chaises ?
Réponse : « Non, il n'y en a pas. » (No, there aren't any.)