A barrel of oil pours out 25 kilograms, pours out (3/5), and uses (1/5) of the poured out, how many kilograms are used?
一桶油倒出25千克，倒出(3/5)，倒出的又用去(1/5)，用去多少千克？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">25 * (1/5)</gadget>
<output>5</output>

<result>5</result>