In a math competition with a total score of 100 points, Xiao Ming completed all the questions and got 79 points. The rules of the competition: 5 points for each correct answer, 2 points for a wrong question, and no points for no answer. Xiao Ming gets it right How many questions?
小明在一次总分为100分的数学竞赛中，题目全部完成，实得79分，竞赛规则：每做对一题得5分，错一题扣2分，不做不扣分，小明做对了几道题？
<gadget id="calculator">100 - 79</gadget>
<output>21</output>

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

<gadget id="calculator">21 / 7</gadget>
<output>3</output>

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

<result>7</result>