There are 100 students taking the exam, the average score is 63 points, the average score of boys is 60 points, and the average score of girls is 70 points, how many girls take the exam?
有100名学生考试，平均分63分，男生平均分60分，女生平均分70分，参加考试的女生有多少人？
<gadget id="calculator">70 * 100</gadget>
<output>7_000</output>

<gadget id="calculator">100 * 63</gadget>
<output>6_300</output>

<gadget id="calculator">7_000 - 6_300</gadget>
<output>700</output>

<gadget id="calculator">70 - 60</gadget>
<output>10</output>

<gadget id="calculator">700 / 10</gadget>
<output>70</output>

<gadget id="calculator">100 - 70</gadget>
<output>30</output>

<result>30</result>