If a rectangle is extended by 2 centimeters, it becomes a square with a perimeter of 24 centimeters. What is the area of the original rectangle in square centimeters?
一个长方形，将它的宽延长2厘米，就变成了一个周长是24厘米的正方形，原来长方形的面积是多少平方厘米．
<gadget id="calculator">24 / 4</gadget>
<output>6</output>

<gadget id="calculator">6 - 2</gadget>
<output>4</output>

<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<result>24</result>