There are 9 rows of seats upstairs in a movie theater, each row has 40 seats, and the number of seats downstairs is twice that of the upstairs. How many seats are there downstairs?
电影院楼上有9排座位，每排40个，楼下的座位是楼上的2倍，楼下有多少个座位？
<gadget id="calculator">40 * 9 * 2</gadget>
<output>720</output>

<result>720</result>