A shopping mall is holding an event, and all products are sold at a 20% discount. How much can a product with an original price of 200 yuan be cheaper after the discount.
某商场搞活动，商品一律八折出售，原价为200元的商品打折后能便宜多少元．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">200 * (1/5)</gadget>
<output>40</output>

<result>40</result>