barrel of oil weighs 30 kilograms, if (5/6) of it is used, how many kilograms are used.
一桶油重30千克，用去它的(5/6)，用去多少千克．
<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">30 * (5/6)</gadget>
<output>25</output>

<result>25</result>