Embroider lace on the four sides of a square tablecloth with a side length of 20 decimeters. What is the perimeter of the lace in decimeters?
给一个边长20分米正方形的桌布的四边绣上花边，花边的周长是多少分米？
<gadget id="calculator">20 * 4</gadget>
<output>80</output>

<result>80</result>