The canteen used 1.6 tons of coal in February, saving 20% compared to January. How many tons of coal is used in January? What is the column
食堂二月份用煤1.6吨，比一月份节约20%．一月份用煤多少吨？列式为多少
<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">1.6 / (4/5)</gadget>
<output>2</output>

<result>2</result>