The actual investment of a project is 6.8 million yuan, which is 15% less than the plan, so how much is the planned investment.
一项工程实际投资680万元，比计划节约15%，那么计划投资多少万元．
<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">1 - (3/20)</gadget>
<output>17/20 = around 0.85</output>

<gadget id="calculator">680 / (17/20)</gadget>
<output>800</output>

<result>800</result>