After half of a barrel of oil is used, the weight of the barrel is 23 kg, and after half of the oil is used, the weight of the barrel is 12 kg. How many kilograms of oil are in this barrel?
一桶油用去一半后，连桶称重23千克，再用去一半后，连桶称重12千克，这个桶共装油多少千克？
<gadget id="calculator">23 - 12</gadget>
<output>11</output>

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

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

<gadget id="calculator">11 / (1/4)</gadget>
<output>44</output>

<result>44</result>