Countable nouns refer to individual things and we can use them in the singular or plural. Uncountable nouns refer to things we consider a whole or mass and cannot be counted.
Countable nouns:
We can put numbers and indefinite articles in front of countable nouns.
We cannot use singular countable nouns without articles or possessive pronouns (a/the/your).
We can use some/any/(a) few/many with plural countable nouns.
Uncountable nouns:
Materials, liquids, and collections are often uncountable nouns.
We use some/any/little/much with uncountable nouns.
We can use many uncountable nouns without an article or possessive pronoun.