Xiaohua scored 86 points in a math competition. There were 20 questions in this competition. If you answered a question correctly, you would get 5 points.
一次数学竞赛小华得了86分，这次竞赛一共20题，答对一题得5分，答错一题或不做倒扣2分，小华答对多少题．
<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>