If the width of a rectangle is 4 cm and its length is 2 cm, what is its area?
一个长方形的宽是4cm，比长短2cm，它的面积是多少．
<gadget id="calculator">4 + 2</gadget>
<output>6</output>

<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<result>24</result>