Amount Vs Number

Amount refers to a quantity of something (a singular noun) that cannot be counted- a large amount of money. Number refers to countable items (a plural noun). With most plurals it is better to use number- a large number of mistakes.

• The amount of money paid is none of my concern.
• A large number of teachers have gone on strike.

Note: A number of (many) is plural in sense and takes a plural verb.(A number of people were shot dead.) The number of (= a mathematical or numerical figure) is singular. It takes a singular verb. (The number of boys present is very small)