The price of a product is 20% lower this year than last year, and last year is 20% lower than the previous year. How much is this year lower than the previous year?
一种产品，今年比去年售价降低20%，去年比前年售价降低20%，今年比前年降低多少．
<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">(4/5) * (4/5)</gadget>
<output>16/25 = around 0.64</output>

<gadget id="calculator">1 - (16/25)</gadget>
<output>9/25 = around 0.36</output>

<result>9/25 = around 0.36</result>