A barrel of oil weighs 12.6 kilograms, and the weight of the barrel after half of it is used up is 7.6 kilograms. How many kilograms of oil are there in the original barrel?
一桶油连桶重12.6千克，用去一半后连桶重7.6千克，请问原来的桶里有油多少千克？
<gadget id="calculator">12.6 - 7.6</gadget>
<output>5</output>

<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<result>10</result>