There are 10 questions in a math competition, 10 points for one correct answer, -5 points for one wrong answer, Xiao Ming finally got 55 points, how many questions did he answer correctly?
一次数学竞赛共10题，答对一题得10分，答错一题得-5分，小明最后共得了55分，他答对了几道题？
<gadget id="calculator">10 * 10</gadget>
<output>100</output>

<gadget id="calculator">100 - 55</gadget>
<output>45</output>

<gadget id="calculator">10 + 5</gadget>
<output>15</output>

<gadget id="calculator">45 / 15</gadget>
<output>3</output>

<gadget id="calculator">10 - 3</gadget>
<output>7</output>

<result>7</result>