A barrel of oil weighs 64 kilograms. After pouring out half of the barrel, pour out half of the oil in the barrel. At this time, the weight of the barrel is still 19 kilograms. How many kilograms does the barrel of oil weigh?
一桶油连桶重64千克，先倒出一半后，再倒出桶中油的一半，这时连桶重还有19千克，求原来这桶油重多少千克？
<gadget id="calculator">64 - 19</gadget>
<output>45</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) * (1/2)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/2) + (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">45 / (3/4)</gadget>
<output>60</output>

<result>60</result>