There are 20 multiple-choice questions in the mathematics competition. 1 correct answer is worth 5 points, and 1 point is deducted for wrong answer or no answer. Xiao Wang scored 82 points in the competition. How many questions did he answer correctly?
数学竞赛共20道选择题，答对1题得5分，答错或不答倒扣1分，小王同学在竞赛中得了82分，他答对了多少题．
<gadget id="calculator">20 * 5</gadget>
<output>100</output>

<gadget id="calculator">100 - 82</gadget>
<output>18</output>

<gadget id="calculator">5 + 1</gadget>
<output>6</output>

<gadget id="calculator">18 / 6</gadget>
<output>3</output>

<gadget id="calculator">20 - 3</gadget>
<output>17</output>

<result>17</result>