Penguin Publishing House published a set of "Genius Wisdom" series of books. The publishing house designed a beautiful book box for this series of books. The price of this series of books together with the book box is 280 yuan. The bookstore allows customers to buy only the books without the book box. If the book is 230 yuan more expensive than the book box, what is the price of the book box?
企鹅出版社出版了一套《天才智慧》丛书，出版社为这套丛书设计了一个漂亮的书盒，这套丛书连同书盒售价280元，书店允许顾客只买书而不买书盒．如果书价比书盒贵230元，那么书盒价为多少元．
<gadget id="calculator">280 - 230</gadget>
<output>50</output>

<gadget id="calculator">50 / 2</gadget>
<output>25</output>

<result>25</result>