Number has both meaning of "index" and "quantity". I am often confused by this in writing sentences such as:
- The conversion between the number of books and total pages is simple. (quantity)
- The number of book on that shelf is 5 counting from left. (index)
My questions are:
- Is the second sentence grammatically correct?
- How to discriminate these two scenarios?
UPDATE:
According to this dictionary, number can be used as "position in series" or "quantity". For sentence:
Room number is 5
Is that correct to turn this statement into questions like:
what is the number of room? (what position)
As Stuart comments: "Using singular vs plural indicates whether you're talking about book number 5 or five books.", if I want to question the quantity of rooms, should I say:
what is the number of rooms? (what quantity)