Transfer (1/5) of the grain stored in warehouse A to warehouse B, then the grain in the two warehouses will be equal. It turns out that Warehouse A is more than Warehouse B, which is equivalent to the amount of Warehouse B
把甲仓存粮的(1/5)调入乙仓，则两仓的粮食相等．原来甲仓比乙仓多的相当于乙仓的多少
<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>