There are three piles of sand, the first pile of sand is (7/2) tons, which is (7/9) heavier than the second pile of sand, the weight of the third pile of sand is (1/5) more than the second pile, and the third pile of sand How many tons more than the second pile?
有三堆沙，第一堆沙有(7/2)吨，是第二堆沙重的(7/9)，第三堆沙的重量比第二堆多(1/5)，第三堆沙比第二堆多多少吨？
<gadget id="calculator">7 / 2</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">7 / 9</gadget>
<output>7/9 = around 0.777778</output>

<gadget id="calculator">(7/2) / (7/9)</gadget>
<output>9/2 = around 4.5</output>

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

<gadget id="calculator">(9/2) * (1/5)</gadget>
<output>9/10 = around 0.9</output>

<result>9/10 = around 0.9</result>