A book has 40 pages, each page has 23 lines, and each line has about 25 characters. How many characters does this book have?
一本书共有40页，每页有23行，每行大约有25个字，这本书大约有多少个字？
<gadget id="calculator">25 * 23 * 40</gadget>
<output>23_000</output>

<result>23_000</result>