A rectangle is 6 cm long and 4 cm wide, what is its perimeter in cm?
一个长方形长6厘米，宽4厘米，它的周长是多少厘米．
<gadget id="calculator">6 + 4</gadget>
<output>10</output>

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

<result>20</result>