A rectangle has a perimeter of 48 cm and a width of 4 cm, what is the area of the rectangle in square centimeters?
一个长方形周长是48厘米，宽是4厘米，这个长方形的面积是多少平方厘米．
<gadget id="calculator">48 / 2</gadget>
<output>24</output>

<gadget id="calculator">24 - 4</gadget>
<output>20</output>

<gadget id="calculator">20 * 4</gadget>
<output>80</output>

<result>80</result>