If the perimeter of a rectangle is 18 meters and the length is 6 meters, what is the area in square meters?
一个长方形的周长是18米，长6米，面积是多少平方米．
<gadget id="calculator">18 / 2</gadget>
<output>9</output>

<gadget id="calculator">9 - 6</gadget>
<output>3</output>

<gadget id="calculator">6 * 3</gadget>
<output>18</output>

<result>18</result>