The perimeter of a square is 40 centimeters, what is its area in square centimetres?
一个正方形的周长是40厘米，它的面积是多少平方厘米
<gadget id="calculator">40 / 4</gadget>
<output>10</output>

<gadget id="calculator">10 * 10</gadget>
<output>100</output>

<result>100</result>