A noun is a thing, e.g. cat, room, exam. Most of the time, we can talk about how many of these things we have: Bobby has three cats at home! It’s amazing how many rooms are empty in our school. I have ...

"Amount" is used for mass nouns that refer to uncountable things (eg. water), whereas "number is used for nouns that refer to things that can be counted (eg. people, years). Even more frequently, we ...