Two barrels of oil are 28 kilograms in total. If (1/8) is poured from barrel A to barrel B, the weight of the two barrels of oil is equal. How many kilograms is less in barrel B than in barrel A?
两桶油共28千克，如果从甲桶倒出(1/8)给乙桶，两桶油重量相等，原来乙桶比甲桶少多少千克．
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 - (1/8)</gadget>
<output>7/8 = around 0.875</output>

<gadget id="calculator">28 / 2 / (7/8)</gadget>
<output>16</output>

<gadget id="calculator">28 - 16</gadget>
<output>12</output>

<gadget id="calculator">16 - 12</gadget>
<output>4</output>

<result>4</result>