I would write this as: I have four identical books, each in its own bag.
ell.stackexchange.com/users/368/John Koerner
Normally you would say: I have 4 bags, each containing the same book.
ell.stackexchange.com/users/10292/Lewis Heslop
Maybe you could write, "I have four copies of the same book, each in a bag."
Of course, this only implies that you have four bags.
If you need to directly mention the fact that you have four bags, you might write something like, "I have four bags, and each has a copy of the same book."
In any case, using the word "copy" might help, since, as @ssdecontrol noted, the construction is pretty cumbersome.
Sorry you can't just leave them as two sentences! :-)
ell.stackexchange.com/users/None/
I have the same book in each of these four bags.
(subject)
I (verb) have (DO adjective) the same (Direct Object)
book (prepositional phrase) in each (prepositional phrase) of these four bags
ell.stackexchange.com/users/10575/JakeANISC
Three notes: First, your original sentence has the wrong article.
Second, your additional sentences aren't using same properly (it's a weird word).
Third, there are a couple ways to make this one sentence.
See below.
First, note that the constructions you're using use the definite determiner/article ( the ) on books .
So, instead of: I have 4 bags.
In each bag, there is a same book.
One would say I have 4 bags.
In each bag, there is the same book.
This is because the books have been mentioned before (in the first sentence of the example).
See the Wikipedia page on definiteness .
Secondly, with your second sentence, the syntax of counters in English can be weird.
For instance, the following is good :
I have 4 books.
But this is not good :
I have 4 same books.
This is because words preceding same require of the :
I have 4 books.
I have 4 of the same book.
I have ten dolls.
I have ten of the same doll.
Note also that nouns modified by of the are singular (book vs books)
Third, as you note, your original sentence sounds weird because it is strange to say something simple like it in two sentences.
As others have pointed out, you could say something like:
I have four bags, each with the same book
However, this is also somewhat weird because you're emphasizing bags without discussing the book much.
The bag sounds more important because it is first, but there isn't much about it.
So, if the book is more important, I would say something like:
I have four copies of the same book in each of these bags.
I have four of the same book with each in a bag.
I have a copy in each of these four bags.
I would expect to hear
I have four bags, each with the same book at a convention or something similar where people are getting free books in bags, and each bag might have a different book.
So, if you're emphasizing you have four bags, but complaining
you have the same books, then this sentence would be used.
ell.stackexchange.com/users/9911/dantiston
As a native (UK) English speaker I would say that you have a number of choices:
I have four copies of the same book, each in a separate bag.
Places the emphasis on the 4 books and clarifies that they are stored in separate bags.
As does: Here are four copies of the book, bagged separately.
While:
I have four bags each containing a copy of the book.
Emphasises the bags and assumes that the specific book is already defined in context.
This might be used at a book launch to describe the door prizes and does not preclude there being other bags that contain other things nor there being other things in each bag.
ell.stackexchange.com/users/10577/Steve Barnes
I would prefer
I have 4 same books each in
bag A, bag B, bag C,
bag D respectively.
or this can be written as
I have four same books each in four different bags.
ell.stackexchange.com/users/8255/A. Prasad
I have 4 identical books in 4 bags.
I have 4 similar books in 4 bags.
I have 4 bags, each contains the same book.
I have 4 bags, each containing the same book.
ell.stackexchange.com/users/8254/Mohamed Hamza
I have 4 bags. In each bag, there is a same book.   I tried to rewrite this as one sentence, but I don't know if it is grammatically correct and  if it conveys the same meaning.   I have 4 same books each in 4 bags.  I have 4 same books each in bag A, bag B, bag C , bag D respectively.   How would you normally say it?
Have I rewritten this correctly?
ell.stackexchange.com
<paraphrasing>
ell.stackexchange.com/questions/34058
ell.stackexchange.com/users/10369/yellow210
I have four bags each containing a copy of the book. I have 4 bags, each containing the same book. I have four copies of the same book, each in a bag. I have four identical books, each in its own bag.  I have four copies of the same book, each in a separate bag.    Multiple expressions are possible, including 'I have four bags, each contains the same book'.
Multiple expressions are possible, including 'I have four bags, each contains the same book'.