The side length of the large square is twice the side length of the small square. The area of the large square is 54 square decimeters larger than the area of the small square. What is the area of the small square in square decimeters?
大正方形的边长是小正方形边长的2倍，大正方形面积比小正方形面积多54平方分米，小正方形的面积是多少平方分米．
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">54 / 3</gadget>
<output>18</output>

<result>18</result>