After a barrel of oil is used up (2/5), there is 48 kilograms left in the barrel. How much does the barrel of oil weigh?
一桶油用去(2/5)后，桶里还剩48千克，这桶油重多少千克．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">48 / (3/5)</gadget>
<output>80</output>

<result>80</result>