A rectangle is 4 cm long and 2 cm wide, what is its perimeter in cm?
一个长方形长4厘米，宽2厘米，它的周长是多少厘米．
<gadget id="calculator">4 + 2</gadget>
<output>6</output>

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

<result>12</result>