For a pile of cement, (1/4) of the total amount was transported for the first time, and 28 tons were transported for the second time, and the remaining (2/5) of the total amount was not transported. How many tons of this pile of cement are there?
一堆水泥，第一次运走总量的(1/4)，第二次运走28吨，还剩下总量的(2/5)没有运，这堆水泥有多少吨？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (1/4) - (2/5)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">28 / (7/20)</gadget>
<output>80</output>

<result>80</result>