If (2/7) of the grain in warehouse A is transferred to warehouse B, then the grain in the two warehouses is equal. It turns out that the grain stored in warehouse B is the amount of warehouse A
把甲仓粮食的(2/7)调入乙仓，则两仓存粮相等．原来乙仓存粮是甲仓的多少
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">1 - (2/7)</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">(5/7) - (2/7)</gadget>
<output>3/7 = around 0.428571</output>

<result>3/7 = around 0.428571</result>