If the perimeter of a square is 8 decimeters, what is the length of its side in centimeters?
一个正方形的周长是8分米，它的边长是多少厘米．
<gadget id="calculator">8 / 4</gadget>
<output>2</output>

<gadget id="calculator">2 * 10</gadget>
<output>20</output>

<result>20</result>