There is a batch of goods in the market. On the first day, (2/5) of the total amount is shipped, and on the second day (1/4) of the total amount is shipped. At this time, there are still 21 tons left. How many tons are there in total in this batch?
商场上有批货，第一天运走了总数的(2/5)，第二天运走总数的(1/4)，这时还剩21吨，这批货共有多少吨？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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

<gadget id="calculator">1 - (2/5) - (1/4)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">21 / (7/20)</gadget>
<output>60</output>

<result>60</result>