There are 6,400 science and technology books in the school library, and there are more science and technology books than story books 100. How many story books are there? (Equation solving)
Solution: There are X story books.
According to the meaning of the question in the equation:
6400=2x+ 100
6300=2x
x=3 150
Answer: The library has 3 150 story books.
Common solution:
(6400-100)/(1+2) = 2100 copies.