The fifth grade of Chaoyang Primary School has two classes, the first class has 51 students, and the second class has 49 students. The average score of all the students in the two classes in the mid-term exam is 81 points. It is known that the average score of the second class is 7 points higher than that of the first class. What is the average score of the second class?
朝阳小学五年级有两个班，一班有51人，二班有49人，期中考试两个班全体同学的平均成绩是81分，已知二班的平均成绩比一班的平均成绩高7分，那么二班的平均成绩是多少分？
<gadget id="calculator">51 + 49</gadget>
<output>100</output>

<gadget id="calculator">100 * 81</gadget>
<output>8_100</output>

<gadget id="calculator">49 * 7</gadget>
<output>343</output>

<gadget id="calculator">8_100 - 343</gadget>
<output>7_757</output>

<gadget id="calculator">7_757 / 100</gadget>
<output>7_757/100 = around 77.57</output>

<gadget id="calculator">(7_757/100) + 7</gadget>
<output>8_457/100 = around 84.57</output>

<result>8_457/100 = around 84.57</result>