If the length of a rectangle is 6 decimeters and the width is 20 centimeters, what is the perimeter?
一个长方形的长是6分米，宽是20厘米，周长是多少．
<gadget id="calculator">20 / 10</gadget>
<output>2</output>

<gadget id="calculator">6 + 2</gadget>
<output>8</output>

<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<result>16</result>