A barrel of oil weighs 12 kilograms, if (2/3) of it is used up, how many kilograms are left?
一桶油重12千克，用去它的(2/3)，还剩多少千克．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 - (2/3)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">12 * (1/3)</gadget>
<output>4</output>

<result>4</result>