A parallelogram-shaped vegetable field has a base length of 90 meters and a height 15 meters shorter than the base. If the average harvest of vegetables per square meter is 6 kilograms, how many kilograms of vegetables are harvested in this field?
一块平行四边形的菜地，底长90米，高比底短15米，如果平均每平方米收青菜6千克，这块地共收多少千克青菜？
<gadget id="calculator">90 - 15</gadget>
<output>75</output>

<gadget id="calculator">90 * 75 * 6</gadget>
<output>40_500</output>

<result>40_500</result>