For a barrel of gasoline, (3/8) tons are used for the first time, and (1/4) tons are used for the second time, and there is still (3/5) tons of gasoline left in the oil barrel. How many tons of gasoline are there in the oil barrel?
一桶汽油，第一次用去了(3/8)吨，第二次用去了(1/4)吨，油桶还剩汽油(3/5)吨，油桶原有汽油多少吨？
<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(5/8) + (1/5)</gadget>
<output>33/40 = around 0.825</output>

<result>33/40 = around 0.825</result>