NUM
n. countable B1 Intermediate num
n. a word or number that describes how many of something there are. You use this when you are counting things or talking about an amount.
n. a word, symbol, or figure representing a mathematical value or quantity. Often used to identify a specific item in a series or to quantify a mass.
Usage
Often followed by the preposition 'of' when quantifying a group of items.
Pitfall
a large amount of peoplea large number of peopleUse 'number' for countable things like people or cars, and 'amount' for uncountable things like water or time.