barrel of oil is 2 kilograms, pour out (1/4) of the oil for the first time, and pour out (1/4) kilograms for the second time, how many kilograms of oil are left in the barrel.
一桶油2千克，第一次倒出油的(1/4)，第二次倒出(1/4)千克，桶内还剩油多少千克．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">2 * (1/4)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">2 - (1/2) - (1/4)</gadget>
<output>5/4 = around 1.25</output>

<result>5/4 = around 1.25</result>