Xiao Ming reads a 312-page storybook, 12 pages a day for 6 days, how many days will he have to read the rest?
小明看一本312页的故事书，每天看12页，看了6天，剩下的还要看几天？
<gadget id="calculator">12 * 6</gadget>
<output>72</output>

<gadget id="calculator">312 - 72</gadget>
<output>240</output>

<gadget id="calculator">240 / 12</gadget>
<output>20</output>

<result>20</result>