A trapezoid has an upper base of 5 decimeters, a lower base of 11 decimeters, and a height of 2 decimeters. What is its area in square decimeters?
一个梯形，它的上底是5分米，下底是11分米，高是2分米，它的面积是多少平方分米．
<gadget id="calculator">5 + 11</gadget>
<output>16</output>

<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">16 * 1</gadget>
<output>16</output>

<result>16</result>