There are 20 questions in a mathematics competition. The scoring standard is to get 5 points for a correct question, and deduct 1 point for each wrong or missed question. Liu Liang scored 64 points in this competition. How many questions did Liu Liang answer correctly? ．
一次数学竞赛共20题，评分标准是做对一道题得5分，每做错或不做一题倒扣1分，刘亮在这次竞赛中得分64分，刘亮一共答对了多少道题．
<gadget id="calculator">20 * 5</gadget>
<output>100</output>

<gadget id="calculator">100 - 64</gadget>
<output>36</output>

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

<gadget id="calculator">36 / 6</gadget>
<output>6</output>

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

<result>14</result>