There are 3 bookshelves in the school, 204 books are placed in each bookshelf, 394 books are lent out, how many books are left?
学校有3个书架，每个书架都放了204本书，借出394本，还剩多少本？
<gadget id="calculator">204 * 3</gadget>
<output>612</output>

<gadget id="calculator">612 - 394</gadget>
<output>218</output>

<result>218</result>