What is the area of the largest square surrounded by a wire 20 meters long?
用一根长20米的铁丝围成一个最大的正方形，这个正方形的面积是多少．
<gadget id="calculator">20 / 4</gadget>
<output>5</output>

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

<result>25</result>