A pile of coal is removed for the first time (2/5), and the second time (1/4), and there are still 35 tons left. How many tons are there in this pile of coal?
一堆煤，第一次运走(2/5)，第二次运走(1/4)，还剩下35吨，这堆煤原来有多少吨？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(2/5) + (1/4)</gadget>
<output>13/20 = around 0.65</output>

<gadget id="calculator">1 - (13/20)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">35 / (7/20)</gadget>
<output>100</output>

<result>100</result>