The output of green vegetables in the suburbs of a certain city last year was 6.4 million kilograms, which is 20% less than this year. What is the total output of green vegetables in this suburb this year?
某市郊区去年绿色蔬菜产量640万千克，比今年少20%，今年这个郊区绿色蔬菜总产量是多少万千克？
<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">640 / (4/5)</gadget>
<output>800</output>

<result>800</result>