Lele was reading a 251-page storybook and accidentally closed it. He remembered that the sum of the page numbers of the two pages he had just read was 101. If Lele reads 40 pages a day, how many days will it take to finish reading the rest?
乐乐正在读一本251页的故事书，不小心合上了，他记得刚读完的两页页码之和是101．如果乐乐每天读40页，剩下的还要几天才能读完？
<gadget id="calculator">251 - 51</gadget>
<output>200</output>

<gadget id="calculator">200 / 40</gadget>
<output>5</output>

<result>5</result>