As shown in the figure, it can be seen from the figure that if one group subtracts two books and three groups subtracts three books, there will be as many as two groups.

Therefore, (23-2-3) is the book number of three groups. Divided by 3, the book number of the two groups is 6? Ben.

Therefore, one group is 6+2=8 books; The three groups are 6+3=9 books or 8+ 1=9 books.