There is a batch of coal in the freight yard, 20% of the total amount is transported away for the first time, and 40% of the total amount is transported away for the second time. A total of 60 tons are transported in the two times. How many tons of coal are left in this batch?
货场有一批煤，第一次运走总数的20%，第二次运走总数的40%，两次一共运走60吨，这批煤还剩多少吨没有运走？
<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">60 / (3/5)</gadget>
<output>100</output>

<gadget id="calculator">100 - 60</gadget>
<output>40</output>

<result>40</result>