What is the area of a square frame surrounded by an iron wire 20 decimeters long?
把一根长20分米的铁线围成一个正方形框架，它的面积是多少平方分米
<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<gadget id="calculator">5 * 5</gadget>
<output>25</output>

<result>25</result>