A barrel of oil weighs 1 kilogram, if (5/6) kilograms are used up, how many kilograms are left?
一桶油重1千克，用去(5/6)千克，还剩多少千克．
<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>

<result>1/6 = around 0.166667</result>