The actual coal consumption is 20% less than the plan, and what percentage of the actual coal consumption is the plan?
实际用的比计划节约20%，实际用煤是计划的百分之几？
<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>

<result>4/5 = around 0.8</result>