A storybook, Honghong reads 40 pages every day, and after reading for a week, there are 320 pages left. How many pages does this storybook have?
一本故事书，红红每天看40页，看了一个星期后还剩320页没有看，这本故事书有多少页？
<gadget id="calculator">7 * 40</gadget>
<output>280</output>

<gadget id="calculator">280 + 320</gadget>
<output>600</output>

<result>600</result>