The two warehouses in the north and the south used to have the same amount of rice. The south warehouse shipped out (1/5) on the first day and 180 tons on the second day; The 120 tons were shipped out in the next day, and the remaining rice in the two warehouses was still the same. The two warehouses in the north and the south used to have how many tons of rice each.
南北两仓原有同样多的大米，南仓第一天运出(1/5)，第二天运出180吨；北仓第一天运出的与剩下的比是1：3，第二天运出120吨，这时两仓剩下的大米还是同样多．南北两仓原来各有大米多少吨．
<gadget id="calculator">180 - 120</gadget>
<output>60</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/4) - (1/5) - 1</gadget>
<output>-19/20 = around -0.95</output>

<gadget id="calculator">1 + (-19/20)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">60 / (1/20)</gadget>
<output>1_200</output>

<result>1_200</result>