If the perimeter of a square is 4 decimeters, what is its area?
一个正方形的周长是4分米，它的面积是多少．
<gadget id="calculator">4 / 4</gadget>
<output>1</output>

<gadget id="calculator">1 * 1</gadget>
<output>1</output>

<result>1</result>