The area of a trapezoid is 16cm**2, the height is 4cm, the bottom is 5cm, and the upper bottom is m.
一个梯形的面积是16cm**2，高是4cm，下底是5cm，上底是多少m．
<gadget id="calculator">2 / 4</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">16 * (1/2)</gadget>
<output>8</output>

<gadget id="calculator">8 - 5</gadget>
<output>3</output>

<result>3</result>