A barrel of oil weighs 12 kilograms, if (3/4) of it is used up, how many kilograms are left?
一桶油重12千克，用去它的(3/4)，还剩下多少千克．
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">12 * (3/4)</gadget>
<output>9</output>

<gadget id="calculator">12 - 9</gadget>
<output>3</output>

<result>3</result>