There are 20 questions in total, 5 points for one correct answer, 0 points for no answer, 2 points deducted for wrong answer. There are as many wrong answers as there are unanswered questions, and the result is 52 points. How many correct answers? (Arithmetic solution)
一共20道，答对一道得5分，不答得0分，答错倒扣2分．答错和没答的题一样多，结果得52分．答对多少道？(算术办法解)
<gadget id="calculator">20 * 5</gadget>
<output>100</output>

<gadget id="calculator">100 - 52</gadget>
<output>48</output>

<gadget id="calculator">5 + 5 + 2</gadget>
<output>12</output>

<gadget id="calculator">48 / 12</gadget>
<output>4</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">20 - 8</gadget>
<output>12</output>

<result>12</result>