A trapezoid, if the upper base is reduced by 4 cm, becomes a triangle, and the area is reduced by 8 cm2 than the original trapezoid, and if the upper base is increased by 4 cm, it becomes a parallelogram. What is the area of the original trapezoid in square centimeters?
一个梯形，如果上底减少4厘米，就变成一个三角形，面积比原来的梯形减少8平方厘米，如果上底增加4厘米，就变成一个平行四边形．原来梯形的面积是多少平方厘米？
<gadget id="calculator">2 / 4</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">8 * (1/2)</gadget>
<output>4</output>

<gadget id="calculator">4 + 4 + 4</gadget>
<output>12</output>

<gadget id="calculator">2 / 4 / 2</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">12 * 8 * (1/4)</gadget>
<output>24</output>

<result>24</result>