There are 3 piles of rice in the grain field, the first pile weighs (4/5) tons, the second pile weighs (3/8) tons less than the first pile, the third pile is the sum of the mass of the first pile and the second pile, and the third pile weighs (4/5) tons less than the first pile. How much does the pile weigh?
谷场有3堆稻谷，第一堆重(4/5)吨，第二堆比第一堆少(3/8)吨，第三堆是第一堆和第二堆的质量总和，第三堆有多重？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">(4/5) - (3/8)</gadget>
<output>17/40 = around 0.425</output>

<gadget id="calculator">(4/5) + (17/40)</gadget>
<output>49/40 = around 1.225</output>

<result>49/40 = around 1.225</result>