A barrel of oil, 10 kilograms are used, and the remaining is more than used (4/5), how many kilograms are left?
一桶油，用去10千克，剩下的比用去的多(4/5)，还剩多少千克？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 + (4/5)</gadget>
<output>9/5 = around 1.8</output>

<gadget id="calculator">10 * (9/5)</gadget>
<output>18</output>

<result>18</result>