There is a batch of goods at the station, 20% of the total is transported in the morning, and 40% of the total is transported in the afternoon, leaving 16 tons. How many tons are there in this batch of goods?
车站有一批货物，上午运走了总数的20%，下午运走了总数的40%，还剩下16吨，这批货物原来有多少吨？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(1/5) + (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">16 / (2/5)</gadget>
<output>40</output>

<result>40</result>