The coal plant produced 2000 tons of coal last year, which was 20% less than the previous year. How much coal was produced in the previous year?
煤厂去年产煤2000t，前年比去年少20%，前年产煤多少t．
<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">2_000 * (4/5)</gadget>
<output>1_600</output>

<result>1_600</result>