A kind of toy is being promoted on National Day, and it is sold at a 15% discount. Each toy is only sold for 17 yuan. How much is a toy cheaper than the original price?
一种玩具国庆搞促销活动，按八五折优惠出售，每只玩具只卖17元，一只玩具比原价便宜了多少元？
<gadget id="calculator">85 / 100</gadget>
<output>17/20 = around 0.85</output>

<gadget id="calculator">17 / (17/20)</gadget>
<output>20</output>

<gadget id="calculator">20 - 17</gadget>
<output>3</output>

<result>3</result>