Both barrels A and B contain the same amount of oil. After pouring 1/3 of the oil in barrel A into barrel B, what is the amount of oil in barrel A at this time?
甲、乙两桶中原有的油同样多．把甲桶油的(1/3)倒入乙桶后，这时甲桶中的油是乙桶的多少
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 + (1/3)</gadget>
<output>4/3 = around 1.333333</output>

<gadget id="calculator">(2/3) / (4/3)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>