The length of a rectangle is 20 decimeters. If the largest square is cut off from one side, what is the perimeter of the remaining small rectangle?
一个长方形长是20分米，如果从一边剪去一个最大的正方形，剩余那个小长方形的周长是多少分米．
<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<result>40</result>