For a trapezoid, if the upper base is increased by 2 cm and the lower base is decreased by 2 cm, it becomes a square with a side length of 5 cm. What is the area of the trapezoid in square centimeters?
一个梯形，如果上底增加2厘米，下底减少2厘米，就成为一个边长是5厘米的正方形，这个梯形的面积是多少平方厘米．
<gadget id="calculator">5 - 2</gadget>
<output>3</output>

<gadget id="calculator">5 + 2</gadget>
<output>7</output>

<gadget id="calculator">3 + 7</gadget>
<output>10</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">10 * (5/2)</gadget>
<output>25</output>

<result>25</result>