There are 580 pages in a book, and Mr. Li has 30 pages left after reading it for 11 days. How many pages does Mr. Li read every day?
一本书580页，李老师看了11天后还剩下30页．李老师每天看多少页？
<gadget id="calculator">580 - 30</gadget>
<output>550</output>

<gadget id="calculator">550 / 11</gadget>
<output>50</output>

<result>50</result>