Dongdong reads a book with a total of 150 pages. He has already read 90 pages. He needs to finish reading the remaining pages within 5 days. How many pages do he read on average every day?
东东看一本书，一共有150页，已经看了90页，剩下的页数要在5天内看完，平均每天看多少页？
<gadget id="calculator">150 - 90</gadget>
<output>60</output>

<gadget id="calculator">60 / 5</gadget>
<output>12</output>

<result>12</result>