After pouring 1/4 of the oil in barrel A into barrel B, the two barrels of oil weigh the same, so what is the original oil in barrel B?
把甲桶油的(1/4)倒入乙桶后，两桶油同样重，那么原来乙桶油是甲桶的多少
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

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

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

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