For a pile of coal, 1/4 of it was burned on the first day, and 25% of it was burned on the second day, leaving 10 tons. How many tons are there in this pile of coal?
一堆煤，第一天烧了它的(1/4)，第二天烧了它的25%，还剩10吨，这堆煤共有多少吨？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4) - (1/4)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">10 / (1/2)</gadget>
<output>20</output>

<result>20</result>