The length of the rectangle is 40 cm, the width is 10 cm, what is the area in square decimeters
长方形的长是40厘米，宽是10厘米，面积是多少平方分米
<gadget id="calculator">40 * 10</gadget>
<output>400</output>

<gadget id="calculator">400 / 100</gadget>
<output>4</output>

<result>4</result>