The Experimental Primary School held a mathematics competition. For each correct question, 9 points were awarded, and for each wrong answer, 3 points were deducted. There were 12 questions in total. Xiao Wang scored 84 points. How many questions did Xiao Wang get wrong?
实验小学举行数学竞赛，每做对一题得9分，做错一题倒扣3分，共有12道题，小旺得了84分，小旺做错了几道题？
<gadget id="calculator">12 * 9</gadget>
<output>108</output>

<gadget id="calculator">108 - 84</gadget>
<output>24</output>

<gadget id="calculator">9 + 3</gadget>
<output>12</output>

<gadget id="calculator">24 / 12</gadget>
<output>2</output>

<result>2</result>