For a trapezoidal vegetable garden, the upper base is 15 meters, the lower base is 25 meters, and the height is 20 meters. During the harvest, 10 kilograms of vegetables are harvested per square meter. How many kilograms of vegetables are harvested in this vegetable field?
一块梯形的菜园，上底是15米，下底是25米，高是20米，丰收的时候每平方米采收菜10千克，这块菜地共收菜多少千克？
<gadget id="calculator">15 + 25</gadget>
<output>40</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">40 * 10</gadget>
<output>400</output>

<gadget id="calculator">400 * 10</gadget>
<output>4_000</output>

<result>4_000</result>