What is the difference in meaning between:
Two score of books.
Two score books.
What is the difference in meaning between:
Two score of books.
Two score books.
The simplest rule I can offer is that the usage of "score" meaning 20 is exactly the same as the use of "dozen" meaning 12.
The only difference is that dozen is still widely used and score is not.
I have two dozen books on my shelf <----> I have two score books on my shelf.
I have dozens of books on my shelf <----> I have scores of books on my shelf
Note that the mention of books for keeping scores during a sporting event is a red herring. These are written as score-books with a hyphen. So:
I have two score-books on my shelf.
I think "dozen" and "score" work the same. Like 'dozen', we usually use 'score' (meaning 'twenty') without 'of' after a number :
e.g. "three score years and ten" ( = 70 years).
Similarly, it is right to say :
Two score books (NOT, two score of books)
But when 20 items will be selected from a particular group, you can say :
"A score of your choicest books" Or, "Two score of the books from this shelf".
However, "scores of books" means "a lot of books".
The correct way is
Forty books.
You can use "score", rarely, in the plural to mean "a significant number but less than hundreds". You use it with "of"
Scores of books were lost in the fire.
But when you mean exactly 20 the use of the word score is obsolete. You should use normal numbers and say "forty books" and not "two score".
Two score of books = 40 books, assuming the antiquated use of score = 20
Two score books = 2 note books for the purpose of keeping score (or tally) for sports, events or competitions etc.