The area of the trapezoid is 54m**2, the height is 6m, the upper base is 5m, and the lower base is m.
梯形的面积是54m**2、高是6m、上底是5m、下底是多少m．
<gadget id="calculator">2 / 6</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">54 * (1/3)</gadget>
<output>18</output>

<gadget id="calculator">18 - 5</gadget>
<output>13</output>

<result>13</result>