Kobayashi reads a 494-page story book, 13 pages a day, and now there are 351 pages left. How many days has Kobayashi been reading?
小林读一本494页的故事书，每天读13页，现在还剩351页，小林已经读了多少天？
<gadget id="calculator">494 - 351</gadget>
<output>143</output>

<gadget id="calculator">143 / 13</gadget>
<output>11</output>

<result>11</result>