In the knowledge contest, there are 10 judgment questions. The scoring rules are: 2 points for each correct answer, and 2 points deducted for each wrong answer. Although Xiaohua answered all the questions, she only got 12 points. May I ask her to answer? How many questions did you miss?
在知识竞赛中，有10道判断题，评分规定：每答对一题得2分，答错一题倒扣2分，小华同学虽然答了全部的题目，但只得了12分，请问她答错了几道题？
<gadget id="calculator">2 * 10</gadget>
<output>20</output>

<gadget id="calculator">20 - 12</gadget>
<output>8</output>

<gadget id="calculator">2 + 2</gadget>
<output>4</output>

<gadget id="calculator">8 / 4</gadget>
<output>2</output>

<result>2</result>