What is the difference between 수, 양, 분량, 수량 ? and How do you use it?
대회에서 발표할 원고의 양은 제한이 없다.
Becaue i confused about how to use 수, 양.. so i'm wondering what happen if i use "수" instead of "양" in this sentence.
Please explain it for me ! And give me many more examples for it .
Thank you so much !

Question

What is the difference between 수, 양, 분량, 수량 ? and How do you use it?
대회에서 발표할 원고의 양은 제한이 없다.
Becaue i confused about how to use 수, 양.. so i'm wondering what happen if i use "수" instead of "양" in this sentence. 
Please explain it for me ! And give me many more examples for it .
Thank you so much !

Answer

As a definition 수 is quantity/number/count/many; 양 is amount/volume/much; 분량 is divided amount; 수량 is combination of number and amount. For instance,
많은 사람 수 --- A large number of people
적은 물의 양 --- A small amount of water
오늘의 숙제 분량 --- A volume of today's designated(divided for today) homework
물건의 수량 --- A size(as a quantity and/or amount) of stuff
I wish your better understanding. Thanks.