In the knowledge contest, there are 10 true or false questions. Grading rules: 2 points are awarded for each correct answer, and 1 point will be deducted for each incorrect answer. Although Xiao Ming answered all the questions, he only scored 14 points in the end. May I ask: How many questions did he answer wrong?
在知识竞赛中，有10道判断题．评分规定：每答对一题得2分，答错一题要倒扣一分．小明同学虽然答了全部的题目，但最后只得了14分，请问：他答错了几题？
<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<gadget id="calculator">20 - 14</gadget>
<output>6</output>

<gadget id="calculator">2 + 1</gadget>
<output>3</output>

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

<result>2</result>