A singular noun names one person, animal, place or thing. A plural noun names more than one person, animal, place, or thing.
We often add -s or -es at the end of a noun to show more than one.

Let us look at the examples.
- Tara sees one girl at the gate and two girls near the swing.
- She packs one box of crayons, and her friends bring five boxes of crayons.