A rectangular vegetable field is 9 meters long and 6 meters wide. This vegetable field has a total of 648 kilograms of vegetables, how many kilograms of vegetables per square meter on average?
一块长方形菜地，长是9米，宽是6米．这块菜地一共收青菜648千克，平均每平方米收青菜多少千克？
<gadget id="calculator">9 * 6</gadget>
<output>54</output>

<gadget id="calculator">648 / 54</gadget>
<output>12</output>

<result>12</result>