In an exam, the average score of Class A is 95, the average score of Class B is 88, and the total average score is 91. Class A has 7 fewer students than Class B. How many students are there in Class A?
一次考试，甲班平均分是95，乙班平均分是88，总平均分是91，甲班比乙班少7人，甲班有多少人？
<gadget id="calculator">91 * 7</gadget>
<output>637</output>

<gadget id="calculator">88 * 7</gadget>
<output>616</output>

<gadget id="calculator">637 - 616</gadget>
<output>21</output>

<gadget id="calculator">88 - 91 - 91</gadget>
<output>-94</output>

<gadget id="calculator">95 + (-94)</gadget>
<output>1</output>

<gadget id="calculator">21 / 1</gadget>
<output>21</output>

<result>21</result>