There is 1 barrel of oil, and the total weight of the barrel is 52 kg. After pouring out half of the oil, the remaining oil weighed 27 kg even in barrels. How many kilograms does the barrel weigh?
有1桶油，连桶共重52千克．倒出一半的油后，剩下的油连桶共重27千克．问桶重多少千克？
<gadget id="calculator">52 - 27</gadget>
<output>25</output>

<gadget id="calculator">25 * 2</gadget>
<output>50</output>

<gadget id="calculator">52 - 50</gadget>
<output>2</output>

<result>2</result>