There are 20 questions in one test, 5 points for one correct answer, 3 points deducted for one wrong answer and 3 points for not doing it correctly, Liu Hai scored 60 points for this test; Question: How many questions did he get right?
一次考试有20道题，做对一题得5分，做错一题和没有做扣3分，刘海这次考试得了60分；问：他作对了几道题？
<gadget id="calculator">20 * 5</gadget>
<output>100</output>

<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>