8. (3 points) Mingming practices writing with a brush pen by copying a calligraphy book. When copying it for the first time, he writes 25 characters every day. When copying it for the second time, he writes 3 more characters each day. As a result, he finishes the second copy exactly 3 days earlier than the first. Therefore, this calligraphy book has $\qquad$ characters.

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8. (3 points) Mingming practices writing with a brush pen by copying a calligraphy book. When copying it for the first time, he writes 25 characters every day. When copying it for the second time, he writes 3 more characters each day. As a result, he finishes the second copy 3 days earlier than the first. How many characters are there in the book?

【Analysis】Let $x$ be the number of days it takes to copy the book for the first time, then it takes $x-3$ days for the second time. According to the relationship: the number of days for the first copy $\times$ 25 characters per day $=$ the number of days for the second copy $\times$ the number of characters written each day during the second copy, we can set up an equation to solve for the number of days for the first copy, and then find out how many characters are in the book.

【Solution】Solution: Let $x$ be the number of days it takes to copy the book for the first time,
$$
\begin{aligned}
25 x & =(25+3) \times(x-3) \\
25 x & =28 x-84 \\
3 x & =84 \\
x & =28, \\
28 & \times 25=700 \text { (characters)}
\end{aligned}
$$

Answer: The book has a total of 700 characters.
Therefore, the answer is: 700.
【Comment】This problem tests the ability to set up and solve equations in practical problems. The key is to set up an equation based on the relationship: the number of days for the first copy $\times$ 25 characters per day $=$ the number of days for the second copy $\times$ the number of characters written each day during the second copy.