There are 15 questions in one test paper, 6 points are awarded for answering one question correctly, 4 points are deducted for one wrong answer, and Xiao Ming gets 0 points for answering all the questions, so how many questions did he answer correctly in total?
一张试卷共有15道题，答对一道题得6分，答错一道题扣4分，小明答完了全部的题目却得了0分，那么他一共答对了多少道题．
<gadget id="calculator">4 * 15</gadget>
<output>60</output>

<gadget id="calculator">60 + 0</gadget>
<output>60</output>

<gadget id="calculator">6 + 4</gadget>
<output>10</output>

<gadget id="calculator">60 / 10</gadget>
<output>6</output>

<result>6</result>