There were 20 questions in a certain mathematics competition, and each correct answer was worth 5 points. If a question was wrong, not only no points, but also 2 points were deducted. In this competition, Xiao Ming scored 86 points. Ask: How many questions did he answer correctly?
某次数学竞赛共有20条题目，每答对一题得5分，错了一题不仅不得分，而且还要倒扣2分，这次竞赛小明得了86分，问：他答对了几道题？
<gadget id="calculator">20 * 5</gadget>
<output>100</output>

<gadget id="calculator">100 - 86</gadget>
<output>14</output>

<gadget id="calculator">5 + 2</gadget>
<output>7</output>

<gadget id="calculator">14 / 7</gadget>
<output>2</output>

<gadget id="calculator">20 - 2</gadget>
<output>18</output>

<result>18</result>