New Year's Day promotion, a sweater with an original price of 100 yuan is only sold for 85 yuan, how much has the price been reduced.
元旦促销，一件原价100元的毛衣只售85元，降价了多少．
<gadget id="calculator">100 - 85</gadget>
<output>15</output>

<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<result>3/20 = around 0.15</result>