There are two bags of rice, pour (1/5) from bag A to bag B, then the weight of the two bags of rice is the same, how much more bag A is than bag B
有两袋大米，从甲袋中倒出(1/5)给乙袋，则两袋大米一样重，原来甲袋比乙袋多多少
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5) - (1/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/5) / (3/5)</gadget>
<output>2/3 = around 0.666667</output>

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