A storybook has 216 pages in total, and Naughty reads 18 pages a day on average. How many days does it take him to finish reading this storybook?
一本故事书共有216页，淘气平均每天看18页，他需要几天才能看完这本故事书？
<gadget id="calculator">216 / 18</gadget>
<output>12</output>

<result>12</result>