Pluriel (Plural)

When there is more than one person or thing, we often add an S to the word.

For example,  

le  bébé  (the baby)  becomes  les  bébés  (the babies)

le  garçon  (the boy)  becomes  les  garçons  (the boys)

la  fille  (the girl)  becomes  les  filles  (the girls)

un  bébé  (a baby)  becomes  des  bébés  (many babies)

une  maison  (a house)  becomes  des  maisons  (many houses)

 

le  grand  lac  (the big lake)  becomes  les  grands  lacs  (the big lakes)

une  jolie  fille  (a pretty girl)  becomes  des  jolies  filles

 

There are exceptions, for example,

le  cheval  (the horse)  becomes  les  chevaux  (the horses)

le  couteau  (the knife)  becomes  les  couteaux  (the knives)

un jeu  (a game)  becomes  des  jeux  (many games)

Don't worry about the exceptions, The students will learn them little by little.

The important thing, your child understand the patterns or rules for plural:

le, la  (the)  becomes  les  (the)

un  (a)  becomes  des  (many)

Words like petit or chat (adjectives & nouns) generally have an S added to them.

petits  chats  (small  cats)