The length of a rectangle is 4.5 decimeters and its width is 2.1 decimeters. What is the area of this rectangle?
一个长方形的长是4.5分米，比宽长2.1分米，这个长方形的面积是多少平方分米？
<gadget id="calculator">4.5 - 2.1</gadget>
<output>2.4</output>

<gadget id="calculator">2.4 * 4.5</gadget>
<output>10.8</output>

<result>10.8</result>