What is the perimeter of a rectangle whose width is 2 meters and whose length is 4 times its width?
一个长方形的宽是2米，长是宽的4倍，它的周长是多少．
<gadget id="calculator">2 * 4</gadget>
<output>8</output>

<gadget id="calculator">8 + 2</gadget>
<output>10</output>

<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<result>20</result>