Xiao Ming reads a 480-page story book and has already read 200 pages. The rest requires 7 days to read, how many pages are read per day on average?
小明看一本480页的故事书，已经看了200页．余下的要求7天看完，平均每天看多少页？
<gadget id="calculator">480 - 200</gadget>
<output>280</output>

<gadget id="calculator">280 / 7</gadget>
<output>40</output>

<result>40</result>