Correct Les petit chats est noir. Explain the agreements.
Les petits chats sont noirs.
- Find the noun and its number
Chats is a masculine plural noun. Les is already the correct plural article.
- Make the adjectives agree
Petit becomes petits and noir becomes noirs to agree with chats in gender and number.
- Match the verb to the subject
Les chats corresponds to ils. The present-tense form of être with ils is sont, not est.
Check all three changes: petit → petits; est → sont; noir → noirs. The meaning stays “The small cats are black.”