"This book is my son's."

Translation: Ce livre est celui de mon fils.

[archiewill9]

I do not understand when to use celle celui ceux celles

[Sitesurf]

In a possessive case like this one, "celui" refers to "le livre" in the form of a pronoun: the one of my son is what "celui de mon fils" literally means.

Since French does not have a possessive apostrophe-S, but a construction with "possession + de + owner", you have to learn this as something to remember.

[AmineHadji1]

Is your question about the difference between celui, celle, ceux and celles? Or is it about when to use Pronoms démonstratifs (Demonstrative pronouns) in general?

[eNdLesSd_VoShUn]

Yes when do you use them?

[Sitesurf]

Please read our Tips&Notes here: https://forum.duolingo.com/comment/30080154

[SrtaRicola]

What is the difference between the four? Here's my guess:
Celui - singular masculine
Celle - singular feminine
Ceux - plural masculine
celles - plural feminine
Is that right?

[andriana2406]

Would you be able to say "Ce livre est de mon fils"?

[Sitesurf]

Please read the explanations above.