A barrel of oil weighs 158 kilograms, and after half of the oil is used, the weight of the barrel is 82 kilograms. How many kilograms of oil is there?
一桶油连桶重158千克，用去一半油后，连桶重82千克．原来有油多少千克？
<gadget id="calculator">158 - 82</gadget>
<output>76</output>

<gadget id="calculator">76 * 2</gadget>
<output>152</output>

<result>152</result>