A rectangular map of China is 6 decimeters long, and its width is 2 decimeters less than its length. What is the circumference of this map in decimeters?
一个长方形中国地图长6分米，宽比长少2分米．这张地图的周长是多少分米？
<gadget id="calculator">6 - 2</gadget>
<output>4</output>

<gadget id="calculator">4 + 6</gadget>
<output>10</output>

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

<result>20</result>