The canteen used 1,600 kilograms of coal in February, 20% less than in January. How many kilograms of coal is used in January?
食堂二月份用煤1600千克，比一月份节约20%．一月份用煤多少千克？
<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">1_600 / (4/5)</gadget>
<output>2_000</output>

<result>2_000</result>