Use a batch of paper to order exercise books, each with 40 pages can order 800 copies, if each book has 50 pages, how many copies can be ordered?
用一批纸订练习本，每本40页可以订800本，如果每本订50页，可以订多少本？
<gadget id="calculator">40 * 800</gadget>
<output>32_000</output>

<gadget id="calculator">32_000 / 50</gadget>
<output>640</output>

<result>640</result>