On the day of "June 1st", Xinhua Bookstore held a sales promotion, and all books were sold at 15% off the original price. Xiaohong bought a set of "Andersen's Fairy Tales" series with an original price of 200 yuan. How much is it cheaper than the original price after the discount?
"六•一"节那天，新华书店举行促销活动，所有书按原价打八五折出售．小红买了一套原价是200元的《安徒生童话》丛书，打折后比原价便宜多少元？
<gadget id="calculator">85 / 100</gadget>
<output>17/20 = around 0.85</output>

<gadget id="calculator">200 * (17/20)</gadget>
<output>170</output>

<gadget id="calculator">200 - 170</gadget>
<output>30</output>

<result>30</result>