The school held a singing competition on June 1st. Classes 3 and 2 lined up in 4 rows, with 10 people in the first row, and each row after that had 2 more people than the previous row. How many people from Class 3 and 2 participated in the singing competition?
六一节学校举行歌咏比赛，三2班排成4排，第一排有10人，往后每一排都比前一排多2人，三2班共有多少人参加歌咏比赛．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<gadget id="calculator">10 + 6</gadget>
<output>16</output>

<gadget id="calculator">10 + 12 + 14 + 16</gadget>
<output>52</output>

<result>52</result>