To build a 185-kilometer road, 104 kilometers have been completed in the first 13 months, and the remaining projects are required to be completed within 9 months. How many kilometers should be repaired on average every month?
修一条185千米的公路，前13个月已经修完104千米，剩下的工程要求在9个月内完工，平均每个月应修多少千米？
<gadget id="calculator">185 - 104</gadget>
<output>81</output>

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

<result>9</result>