A pile of coal is removed (1/3) and there are 500 tons left. How many tons is this pile of coal?
一堆煤运走(1/3)还剩500吨，原来这堆煤有多少吨
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">500 / (2/3)</gadget>
<output>750</output>

<result>750</result>