A group of children are playing games on the playground, with 6 people in each group. After playing for a while, they felt that the number of people in each group was too small, so they regrouped. After grouping, there were exactly 9 people in each group, which reduced two groups from the original. How many children are there in total to participate in the game? (Solve and analyze the process by arithmetic method)
一班的小朋友在操场上做游戏，每组6人．玩了一会儿，他们觉得每组人数太少便重新分组，分组后正好每组9人，这样比原来减少了两组．求参加游戏的小朋友一共有多少人？(用算术方法解答并分析过程)
<gadget id="calculator">9 * 2</gadget>
<output>18</output>

<gadget id="calculator">9 - 6</gadget>
<output>3</output>

<gadget id="calculator">18 / 3</gadget>
<output>6</output>

<gadget id="calculator">6 * 6</gadget>
<output>36</output>

<result>36</result>