Dajun and Xiaomei shared 120 tons of water in the first four months of this year. How many tons of water does each household use on average per month?
大军和小美两家今年前4个月一共用水120吨，每户人家平均每个月用水多少吨？
<gadget id="calculator">120 / 4 / 2</gadget>
<output>15</output>

<result>15</result>