If the perimeter of a rectangle is 40 cm and the width is 8 cm, what is the area?
一个长方形的周长是40厘米，宽是8厘米，面积是多少．
<gadget id="calculator">40 / 2</gadget>
<output>20</output>

<gadget id="calculator">20 - 8</gadget>
<output>12</output>

<gadget id="calculator">12 * 8</gadget>
<output>96</output>

<result>96</result>