The charging standard for tap water use by residents in a certain city is as follows: the monthly water consumption of each household does not exceed 4 tons, and the fee is 2.5 yuan per ton; if it exceeds 4 tons, the excess part is charged 3 yuan per ton. According to this standard, Xiaodong's family paid a total of 24.4 yuan for water last month. How many tons of water did his family share last month?
某市居民使用自来水的收费标准如下：每户每月用水量不超过4吨，每吨收费2.5元；若超过4吨，超过部分每吨收费3元．按这个标准，小冬家上月共付水费24.4元，他家上月共用水多少吨？
<gadget id="calculator">2.5 * 4</gadget>
<output>10</output>

<gadget id="calculator">24.4 - 10</gadget>
<output>14.4</output>

<gadget id="calculator">14.4 / 3</gadget>
<output>4.8</output>

<gadget id="calculator">4.8 + 4</gadget>
<output>8.8</output>

<result>8.8</result>