The perimeter of a square is 16dm, what is its area dm**2.
一个正方形的周长是16dm，它的面积是多少dm**2．
<gadget id="calculator">16 / 4</gadget>
<output>4</output>

<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<result>16</result>