A trapezoidal cabbage field has an upper base of 9 meters, a lower base of 12 meters, and a height of 18 meters. The average yield of cabbage per square meter is 12 kilograms. How many kilograms of cabbage can be produced in this cabbage field?
一块近似梯形的白菜地，它的上底是9米，下底是12米，高是18米，平均每平方米产白菜12千克，这块白菜地共产白菜多少千克？
<gadget id="calculator">9 + 12</gadget>
<output>21</output>

<gadget id="calculator">18 / 2</gadget>
<output>9</output>

<gadget id="calculator">21 * 9</gadget>
<output>189</output>

<gadget id="calculator">12 * 189</gadget>
<output>2_268</output>

<result>2_268</result>