The length of the rectangle is 11 decimeters and the width is 7 decimeters. What is its perimeter?
长方形的长是11分米，宽是7分米，它的周长是多少分米？
<gadget id="calculator">11 + 7</gadget>
<output>18</output>

<gadget id="calculator">18 * 2</gadget>
<output>36</output>

<result>36</result>