A and B have two bags of sugar, pour (2/5) from A bag to B bag, the two bags of sugar are equal. It turns out that bag A weighs the same as bag B.
甲、乙两袋糖，从甲袋倒(2/5)给乙袋，两袋糖则相等．原来甲袋糖的重量是乙袋糖的多少．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/5) * 2</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

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

<result>5</result>