A book has 90 pages, Xiaoxiao has already read 50 pages, and finished the remaining 5 days. How many pages do you read on average per day?
一本书90页，笑笑已经看了50页，剩下的5天看完．平均每天看多少页？
<gadget id="calculator">90 - 50</gadget>
<output>40</output>

<gadget id="calculator">40 / 5</gadget>
<output>8</output>

<result>8</result>