A barrel of oil weighs (3/4) kilograms, if (1/2) kilograms are eaten, how many kilograms are left?
一桶油重(3/4)千克，吃了(1/2)千克，还剩多少千克．
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(3/4) - (1/2)</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>