Xiaohong has 160 story books, twice as many as Xiaoping, and Xiaodong has four times as many as Xiaoping. How many books are there in Xiaodong's storybook?
小红有故事书160本，是小萍故事书本数的2倍，而小冬的本数是小萍的4倍．小冬故事书的本数是多少本？
<gadget id="calculator">160 / 2</gadget>
<output>80</output>

<gadget id="calculator">80 * 4</gadget>
<output>320</output>

<result>320</result>