rectangular flower bed is 4 cm wide and twice as long as it is wide. What is the perimeter of the flower bed?
一个长方形花坛，宽是4厘米，长是宽的2倍，这个花坛的周长是多少？
<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">8 + 4</gadget>
<output>12</output>

<gadget id="calculator">12 * 2</gadget>
<output>24</output>

<result>24</result>