The sixth grade of Guangming Primary School held a mathematics competition. There were 30 test questions in total. If you answered a question correctly, you would get 5 points. If you didn’t answer a question or got a wrong answer, 2 points would be deducted. Xiao Ming got 80 points.
光明小学六年级举行数学竞赛，共30道试题，做对一题得5分，没有做一题或做错一题倒扣2分，小明得了80分，则他做对了多少题．
<gadget id="calculator">5 * 30</gadget>
<output>150</output>

<gadget id="calculator">150 - 80</gadget>
<output>70</output>

<gadget id="calculator">2 + 5</gadget>
<output>7</output>

<gadget id="calculator">70 / 7</gadget>
<output>10</output>

<gadget id="calculator">30 - 10</gadget>
<output>20</output>

<result>20</result>