A square is surrounded by a wire 20 cm long. What is the possible area of the square in square centimeters?
用一根长20厘米的铁丝围成一个正方形，这个正方形的面积可能是多少平方厘米．
<gadget id="calculator">20 / 4</gadget>
<output>5</output>

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

<result>25</result>