For a trapezoid, if the upper base is extended by 10 decimeters, then the area will increase by 8 decimeters squared and become a parallelogram. If the original upper base is 6 decimeters, how many square decimeters is the area of the trapezoid?
一个梯形，如果上底延长10分米，那么面积就增加8平方分米，而且变成了一个平行四边形，如果原来的上底是6分米，那么梯形的面积是多少平方分米？
<gadget id="calculator">6 + 10 + 6</gadget>
<output>22</output>

<gadget id="calculator">2 / 10</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">8 * (1/5)</gadget>
<output>8/5 = around 1.6</output>

<gadget id="calculator">(8/5) / 2</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">22 * (4/5)</gadget>
<output>88/5 = around 17.6</output>

<result>88/5 = around 17.6</result>