Wang Gang participated in a mathematics competition and did 25 questions in total. If he got a question right, he would get 4 points, and if he got a wrong question, 2 points would be deducted. Wang Gang got a total of 58 points. Ask him how many questions he got wrong.
王刚参加数学竞赛，共做了25道题，如果做对一题得4分，做错一题倒扣2分，王刚共得了58分，问他做错了多少道题．
<gadget id="calculator">25 * 4</gadget>
<output>100</output>

<gadget id="calculator">100 - 58</gadget>
<output>42</output>

<gadget id="calculator">4 + 2</gadget>
<output>6</output>

<gadget id="calculator">42 / 6</gadget>
<output>7</output>

<result>7</result>