A pile of coal, its (2/5) was removed for the first time, and its (1/4) was removed for the first time, and there are 140 tons left. How many tons of this pile of coal are there?
一堆煤，第一次运走了它的(2/5)，第一次运走了它的(1/4)，还剩140吨，这堆煤共有多少吨？
<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">1 - (2/5) - (1/4)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">140 / (7/20)</gadget>
<output>400</output>

<result>400</result>