Cut off 6 meters from a section of cloth, just cut off 40% of this section of cloth, how many meters are left in this section of cloth.
一段布剪去6米，正好剪去这段布的40%，这段布还剩多少米．
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">6 / (2/5)</gadget>
<output>15</output>

<gadget id="calculator">15 - 6</gadget>
<output>9</output>

<result>9</result>