A barrel of oil is 10 kilograms, how many kilograms of the barrel of oil (4/5) is used?
一桶油10千克，用去了这桶油的(4/5)，用去了多少千克？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">10 * (4/5)</gadget>
<output>8</output>

<result>8</result>