If the base of a parallelogram is increased by 40% and the height is decreased by ((())/(())), the area of the new parallelogram obtained is half of the original area.
一个平行四边形的底增加40%，高减少((())/(()))，得到的新平行四边形的面积是原面积的一半．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 + (2/5)</gadget>
<output>7/5 = around 1.4</output>

<gadget id="calculator">(1/2) / (7/5)</gadget>
<output>5/14 = around 0.357143</output>

<gadget id="calculator">1 - (5/14)</gadget>
<output>9/14 = around 0.642857</output>

<result>9/14 = around 0.642857</result>