The actual cost of building a building is 2 million yuan, which is 20% less than the plan. How much is the planned cost?
建造一栋楼房，实际用了200万元，比计划节约了20%，计划要用多少万元．
<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">200 / (4/5)</gadget>
<output>250</output>

<result>250</result>