The length of a rectangle is 15 meters, the width is 20 decimeters, what is the area in decimeters**2.
一个长方形的长是15米，宽是20分米，面积是多少分米**2．
<gadget id="calculator">15 * 10</gadget>
<output>150</output>

<gadget id="calculator">150 * 20</gadget>
<output>3_000</output>

<result>3_000</result>