The wholesale price of a certain children's clothing is 30 yuan per piece, and the retail price is 38 yuan per piece. Uncle Wang earned 72 yuan today. How many pieces of children's clothing did Uncle Wang sell today?
某种童装的批发价是每件30元，零售价是每件38元，王叔叔今天赚了72元，王叔叔今天卖了多少件童装？
<gadget id="calculator">38 - 30</gadget>
<output>8</output>

<gadget id="calculator">72 / 8</gadget>
<output>9</output>

<result>9</result>