There are two groups of numbers, the sum of the nine numbers in the first group is 63, the average of the second group is 11, and the average of all the numbers in the two groups is 8. So how many numbers are there in the second group?
有两组数，第一组9个数的和是63，第二组的平均数是11，两个组中所有数的平均数是8．那么第二组有多少个数．
<gadget id="calculator">8 * 9</gadget>
<output>72</output>

<gadget id="calculator">72 - 63</gadget>
<output>9</output>

<gadget id="calculator">11 - 8</gadget>
<output>3</output>

<gadget id="calculator">9 / 3</gadget>
<output>3</output>

<result>3</result>