A square vegetable field with a side length of 9 meters can harvest 8 kilograms of cabbage per square meter on average. How many kilograms of cabbage can be harvested in this vegetable field?
一块正方形菜地，边长9米，平均每平方米收白菜8千克，这块菜地一共收白菜多少千克？
<gadget id="calculator">9 * 9 * 8</gadget>
<output>648</output>

<result>648</result>