The materials in the warehouse are transported to the destination. The first time it is shipped out (1/5), and the second time it is shipped out 720 tons. At this time, 20% of the original materials are left. How many tons are there in this batch of materials?
把仓库的物资运往目的地，第一次运出它的(1/5)，第二次运出720吨，这时还剩下原物资的20%，这批物资共有多少吨？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5) - (1/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">720 / (3/5)</gadget>
<output>1_200</output>

<result>1_200</result>