Happy Valley Zhengtian Cinema has 13 rows of seats, the first row has 42 seats, and the latter row always has 4 more seats than the previous row. How many seats are there in the last row?
欢乐谷正天电影院有13排座位，第一排有42个座位，后一排总比前一排多4个座位，求最后一排有多少个座位？
<gadget id="calculator">13 - 1</gadget>
<output>12</output>

<gadget id="calculator">12 * 4</gadget>
<output>48</output>

<gadget id="calculator">42 + 48</gadget>
<output>90</output>

<result>90</result>