Learn French: Il y a quatre-vingt-dix étudiants dans l'école.

In French, numbers from 80 to 99 involve a bit of math! Quatre-vingts means four twenties (4 x 20 = 80). To say 90, you add ten, making it four-twenty-ten, which is quatre-vingt-dix (80 + 10 = 90).

I learned that 80 is quatre-vingts with an s. Why is there no s in quatre-vingt-dix?

Great observation! The word vingt only takes an s when it is multiplied by another number AND is the very last word in the entire number. Because 90 adds dix at the end, vingt is no longer the final word, so it loses its s.

How do I pronounce the x at the end of dix in this sentence?

Normally, the x in dix sounds like an s or is silent. However, because the next word, étudiants, starts with a vowel, you must connect the words. This connection makes the x sound like a z, so the end of the number sounds like di-z-étudiants.

Does il y a change if I am talking about multiple students?

No, it stays exactly the same! Unlike English, which switches between there is and there are, French uses il y a for both singular and plural. So here, il y a translates perfectly to there are.