A and B have two piles of coal, and give B from pile A (1/5), then the two piles of coal are equal, so how much is A more than B
甲乙两堆煤，从甲堆中(1/5)给乙，则两堆煤相等，原来甲比乙多多少
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 / (4/5)</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">(5/4) * (1/5)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(5/4) - (3/4)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) / (3/4)</gadget>
<output>2/3 = around 0.666667</output>

<result>2/3 = around 0.666667</result>