Countable Nouns:

1. Countable Noun means something that can be counted.

2. Countable Nouns can be Plural.

3. Countable Nouns have singular and plural forms.

4. If the Countable Nouns is singular, then a / an must be placed before it.

5. Examples:   A pen, Two Pens, An Umbrella, Five Umbrellas.

On the other hand,

Uncountable Nouns:

1. Uncountable Noun means something that can't be counted.

2. Uncountable Nouns can't be Plural.

3. Uncountable Nouns have a singular form but no plural form.

4. A / an cannot be placed before Uncountable Nouns.

5. Examples:  Water, Tea, Milk,