A barrel of oil weighs 10 kilograms in total, and if it is sold (2/3), the total weight of the barrels is 4 kilograms. How many kilograms does the oil weigh?
一桶油连桶共重10千克，如果卖去(2/3)，则连桶共重4千克．油重多少千克？
<gadget id="calculator">10 - 4</gadget>
<output>6</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">6 / (2/3)</gadget>
<output>9</output>

<result>9</result>