In order to improve residents' awareness of water conservation, the spring city tap water charges are as follows: 1.8 yuan per ton for each household with no more than 5 tons (including 5 tons) of water per month; 2.8 yuan per ton for the excess water for more than 5 tons. Xiaojun’s family used 9 tons of water in July, how much should they pay for water?
为提高居民节约用水的意识，春城自来水的收费标准是：每月每户用水不超过5吨(包括5吨)，每吨1.8元；超过5吨，超过部分每吨2.8元．小军家7月份用水9吨，应缴水费多少元？
<gadget id="calculator">9 - 5</gadget>
<output>4</output>

<gadget id="calculator">2.8 * 4</gadget>
<output>11.2</output>

<gadget id="calculator">1.8 * 5</gadget>
<output>9</output>

<gadget id="calculator">11.2 + 9</gadget>
<output>20.2</output>

<result>20.2</result>