If a rose is 20% cheaper than a rose, how much is a rose more expensive than a rose.
若一枝月季花比一枝玫瑰花便宜20%，则一枝玫瑰花比一枝月季花贵多少．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(1/5) / (4/5)</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>