After the price of a piece of clothing is reduced by 20%, it is 160 yuan. How much is the price reduction?
一件衣服降价20%后是160元，降价了多少元？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">160 / (4/5)</gadget>
<output>200</output>

<gadget id="calculator">200 - 160</gadget>
<output>40</output>

<result>40</result>