There are 3 students from Ye Xiao Elementary School who participated in the mathematics competition. There are 10 questions in a test paper, 10 points are awarded for each correct answer, and 3 points are deducted for a wrong answer. These 3 students have answered all the questions. For the question, Xiaoming scored 74 points, Xiaohua scored 22 points, and Xiaohong scored 87 points. How many questions did the three of them answer correctly?
叶小小学有3名同学去参加数学竞赛，一份试卷共10道题，答对一题得10分，答错一道不但不得分，还要扣去3分，这3名同学都回答了所有的题目，小明得74分，小华得22分，小红得87分，他们三人共答对多少题？
<gadget id="calculator">10 * 10</gadget>
<output>100</output>

<gadget id="calculator">100 - 74</gadget>
<output>26</output>

<gadget id="calculator">10 + 3</gadget>
<output>13</output>

<gadget id="calculator">26 / 13</gadget>
<output>2</output>

<gadget id="calculator">10 - 2</gadget>
<output>8</output>

<gadget id="calculator">100 - 22</gadget>
<output>78</output>

<gadget id="calculator">78 / 13</gadget>
<output>6</output>

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

<gadget id="calculator">100 - 87</gadget>
<output>13</output>

<gadget id="calculator">13 / 13</gadget>
<output>1</output>

<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">8 + 4 + 9</gadget>
<output>21</output>

<result>21</result>