A whole barrel of oil weighs 96 kilograms, and after half of the oil is used, the weight of the barrel is still 51 kilograms. Find the weight of the empty bucket.
一整桶油，连桶重96千克，用去油的一半后，连桶还重51千克．求空桶的重量．
<gadget id="calculator">96 - 51</gadget>
<output>45</output>

<gadget id="calculator">51 - 45</gadget>
<output>6</output>

<result>6</result>