There is a batch of rice in a rice warehouse. The first time (1/3) was transported away, and the second time 420 tons were transported. At this time, the ratio of the transported rice to the remaining rice is 4:1. How many tons are there in the warehouse? rice?
某大米仓库有一批大米，第一次运走了(1/3)，第二次运走了420吨，这时运走的和剩下的大米比是4：1，仓库里还有多少吨大米？
<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 / 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">420 / (7/15)</gadget>
<output>900</output>

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

<gadget id="calculator">900 * (1/5)</gadget>
<output>180</output>

<result>180</result>