For a project, the actual cost is 10% less than the plan, and the actual cost is the planned amount.
一项工程，实际造价比计划节约10%，实际造价是计划的多少．
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/10)</gadget>
<output>9/10 = around 0.9</output>

<result>9/10 = around 0.9</result>