How to use these phrases?

Hi guys!
I am confusing with these words for many times. Could you tell me full of meanings and usages them?
1> series of sth
2> a variety of …
3> a number of…
4> a large number of…
5>amount of…
6>a great deal of…
Thanks for your full helpings.

A series is a group of things which come one after the other in a set order: a series of numbers. Or just a group of things: he wrote a series of letters to the paper.

Things of different sorts are a variety: I read books on a variety of subjects; the work in the office has a lot of variety; for a variety of reasons, for several different reasons.

A number of means ‘several’: this can happen for a number of reasons.

A large number of and a great deal of mean ‘a lot of’, ‘a large quantity’: a large number of people have complained about it; I have wasted a good deal of time.

Any/a small/a huge,etc. amount of also refers to quantity: she drinks a huge amount of tea.

Also note:

Helping as a noun is a serving or a portion: can I have a second helping of ice cream? :slight_smile:

Thanks to Conchita! :slight_smile: