Learn French: La valise coûte quarante euros. - The suitcase costs 40 euros.

No. Unlike adjectives, almost all French numbers are invariable, meaning they never change their spelling to match the gender or plural of the noun. Whether it is 40 suitcases or 40 books, it is always quarante.

How do I pronounce quarante euros together?

In the word quarante, the final e is silent, leaving a hard 't' sound at the end. When followed by a word starting with a vowel like euros, that 't' links directly to the next word. It flows smoothly together and sounds like "ka-rahn-teu-ro".

Does the word euro always get an s when it is more than one?

Yes! In French, currency names act like regular nouns. Since forty is more than one, you add an s to make it euros. However, the s is silent, so singular euro and plural euros sound exactly the same.

Why does the verb coûte end in -e here?

Coûte comes from the regular -er verb coûter (to cost). Since la valise (the suitcase) is a singular object, it acts as a third-person singular subject (just like "he", "she", or "it"). For regular -er verbs, that ending is always -e.