The original price of a coat is 100 yuan, but now it is sold at a 15% discount. How much is it cheaper than before?
一件上衣原价100元，现在按八五折销售，现在比原来便宜多少元．
<gadget id="calculator">85 / 100</gadget>
<output>17/20 = around 0.85</output>

<gadget id="calculator">1 - (17/20)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">100 * (3/20)</gadget>
<output>15</output>

<result>15</result>