The base of a parallelogram is 10dm, and the height is twice the base, what is the area of the parallelogram in dm**2.
一个平行四边形的底是10dm，高是底的2倍，平行四边形的面积是多少dm**2．
<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<gadget id="calculator">10 * 20</gadget>
<output>200</output>

<result>200</result>