movie theater has 20 rows of seats, the first row has 28 seats, and each row behind has 2 more seats than the front row. How many seats are there in total in this cinema?
一个电影院有20排座位，第一排有28个座位，往后每排都比前排多2个座位．问这个电影院一共有多少个座位？
<gadget id="calculator">20 - 1</gadget>
<output>19</output>

<gadget id="calculator">19 * 2</gadget>
<output>38</output>

<gadget id="calculator">28 + 38</gadget>
<output>66</output>

<gadget id="calculator">28 + 66</gadget>
<output>94</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">94 * 10</gadget>
<output>940</output>

<result>940</result>