There is a grain depot that originally stored a batch of grain. After transporting away (2/3), 5.6 tons of grain were transported in. At this time, the existing grain is the original grain (4/5). How many tons of grain was originally stored in the grain depot?
有一个粮库，原来存有一批粮食，运走(2/3)后，又运进粮食5.6吨，这时现有存粮是原来存粮的(4/5)，粮库原有存粮多少吨？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

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

<gadget id="calculator">1 - (2/3)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(4/5) - (1/3)</gadget>
<output>7/15 = around 0.466667</output>

<gadget id="calculator">5.6 / (7/15)</gadget>
<output>12</output>

<result>12</result>