A rectangle is 4 meters long and its width is half its length. What is its perimeter in meters?
一个长方形是4米，宽是长的一半，它的周长是多少米．
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">4 + 2</gadget>
<output>6</output>

<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<result>12</result>