The price of a picture album is reduced by 15%, and the current price is the original price.
一种画册降价15%，现价是原价的多少．
<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">1 - (3/20)</gadget>
<output>17/20 = around 0.85</output>

<result>17/20 = around 0.85</result>