A real estate in Guangzhou launched a "pre-existing house liquidation special price" activity, the average price was only 15,800 yuan/square meter, and before the price reduction, the average price was 20,000 yuan/square meter, how much was the price cut for this real estate?
广州某楼盘推出"准现房清盘特惠价"活动，均价仅为15800元/平方米，而其降价前，均价在20000元/平方米作用，该楼盘降价了百分之几？
<gadget id="calculator">20_000 - 15_800</gadget>
<output>4_200</output>

<gadget id="calculator">4_200 / 20_000</gadget>
<output>21/100 = around 0.21</output>

<result>21/100 = around 0.21</result>