The length of a rectangle is 4 cm, the width is 3 cm, what is the perimeter in cm?
一长方形长为4厘米，宽为3厘米，周长为多少厘米．
<gadget id="calculator">4 + 3</gadget>
<output>7</output>

<gadget id="calculator">7 * 2</gadget>
<output>14</output>

<result>14</result>