After 20% of 200 kg of chemical fertilizer is used, the remaining 20% is used, how many kg are left
200千克化肥用去20%后，又用去了余下的20%，还剩多少千克
<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">200 * (4/5) * (4/5)</gadget>
<output>128</output>

<result>128</result>