The rice store plans to sell (5/8) tons of rice a day, but it sells (1/2) tons in the morning and (4/5) tons in the afternoon. How many tons more than the original plan actually sells on this day?
米店计划一天卖米(5/8)吨，结果上午卖出(1/2)吨，下午卖出(4/5)吨，这天实际比原计划多卖多少吨？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">(4/5) - (5/8)</gadget>
<output>7/40 = around 0.175</output>

<gadget id="calculator">(1/2) + (7/40)</gadget>
<output>27/40 = around 0.675</output>

<result>27/40 = around 0.675</result>