Arrange the 9 numbers in ascending order, and the average number is 9. If the average number of the first 5 numbers in this group is 8, and the average number of the last 5 numbers is 10, then the median of the 9 numbers What is the number of digits.
把9个数按从小到大的顺序排列，其中平均数是9，如果这组数中前5个数的平均数是8，后5个数的平均数是10，则这9个数的中位数是多少．
<gadget id="calculator">8 * 5</gadget>
<output>40</output>

<gadget id="calculator">10 * 5</gadget>
<output>50</output>

<gadget id="calculator">40 + 50</gadget>
<output>90</output>

<gadget id="calculator">9 * 9</gadget>
<output>81</output>

<gadget id="calculator">90 - 81</gadget>
<output>9</output>

<result>9</result>