Xiao Ming participates in the riddle guessing competition. There are 20 questions in total. It is stipulated that if he guesses correctly, he will get 5 points, and if he guesses wrong, 3 points will be deducted.
小明参加猜谜语比赛，共20题，规定猜对一个得5分，猜错一个倒扣3分(不猜按猜错计算)，小明共得60分，他猜对了几个题？
<gadget id="calculator">100 - 60</gadget>
<output>40</output>

<gadget id="calculator">5 + 3</gadget>
<output>8</output>

<gadget id="calculator">40 / 8</gadget>
<output>5</output>

<gadget id="calculator">20 - 5</gadget>
<output>15</output>

<result>15</result>