A barrel of cooking oil weighs 12 kilograms, and after half of the oil is used, the barrel still weighs 6.5 kilograms. If cooking oil is 5.8 yuan per kilogram, how much does it cost to buy a barrel of oil?
一桶食用油连桶共重12千克，用去油的一半后，连桶还重6.5千克．如果每千克食用油5.8元，买一桶油要多少元？
<gadget id="calculator">6.5 * 2</gadget>
<output>13</output>

<gadget id="calculator">13 - 12</gadget>
<output>1</output>

<gadget id="calculator">12 - 1</gadget>
<output>11</output>

<gadget id="calculator">5.8 * 11</gadget>
<output>63.8</output>

<result>63.8</result>