A power plant originally had 3,000 tons of coal and used up (5/6), how many tons are left.
一个发电厂原有煤3000吨，用去(5/6)，还剩多少吨．
<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">1 - (5/6)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">3_000 * (1/6)</gadget>
<output>500</output>

<result>500</result>