Two granaries, the tonnage of grain stored in warehouse A is (4/5) of that of warehouse B. If 4 tons are taken out from warehouse B and put into warehouse A, the tonnage of grain stored in the two warehouses is exactly the same. How many tons of grain was stored in warehouse A?
两个粮仓，甲仓的存粮吨数是乙仓的(4/5)，如果从乙仓取出4吨放入甲仓，两仓的存粮吨数正好相等，甲仓原来存粮多少吨？
<gadget id="calculator">4 / 5</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">2 / (1/5)</gadget>
<output>10</output>

<gadget id="calculator">4 * 10 * (4/5)</gadget>
<output>32</output>

<result>32</result>