A barrel of oil in the cafeteria weighs 50 kilograms. After eating half of it, the barrel weighs 27 kilograms. How many kilograms does the barrel weigh?
食堂一桶油连桶重50千克，吃了一半后，连桶重27千克，桶重多少千克？
<gadget id="calculator">50 - 27</gadget>
<output>23</output>

<gadget id="calculator">27 - 23</gadget>
<output>4</output>

<result>4</result>