If the width of a rectangle is 5 decimeters and the length is 18 decimeters, what is the perimeter of the rectangle?
一个长方形的宽是5分米，长是18分米，长方形的周长是多少分米．
<gadget id="calculator">18 + 5</gadget>
<output>23</output>

<gadget id="calculator">23 * 2</gadget>
<output>46</output>

<result>46</result>