A rectangular lawn is 2.5 meters wide and twice as long as it is wide. What is the area of the lawn in square meters?
一块长方形草坪的宽是2.5米，长是宽的2倍．这块草坪的面积是多少平方米？
<gadget id="calculator">2.5 * 2 * 2.5</gadget>
<output>12.5</output>

<result>12.5</result>