There are 210 tons of yellow sand to be transported to the construction site. The first time (1/3) of the total is transported away, and the second time 40% of the total is transported away. How many tons must be transported to finish?
有210吨黄沙要运到建筑工地，第一次运走了总数的(1/3)，第二次运走总数的40%，还要运多少吨才能运完？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

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

<gadget id="calculator">1 - (1/3) - (2/5)</gadget>
<output>4/15 = around 0.266667</output>

<gadget id="calculator">210 * (4/15)</gadget>
<output>56</output>

<result>56</result>