A commodity is sold at a 15% discount. If the original price of the commodity is 100 yuan, how much is it cheaper now?
一种商品打八五折销售，如果商品的原价为100元，现在便宜了多少元．
<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>