Wang Li has been reading a 480-page storybook for 4 days, 20 pages a day, and plans to finish the rest in 5 days. How many pages do she need to read on average every day?
王丽看一本480页的故事书，已经看了4天，每天看20页，剩下的准备用5天看完，平均每天要看多少页？
<gadget id="calculator">20 * 4</gadget>
<output>80</output>

<gadget id="calculator">480 - 80</gadget>
<output>400</output>

<gadget id="calculator">400 / 5</gadget>
<output>80</output>

<result>80</result>