A batch of disaster relief materials, (1/4) was transported away on the first day, (2/5) was transported away on the second day, and the rest was shipped out on the third day. How much of this batch of supplies was transported on the third day.
一批救灾物资，第一天运走它的(1/4)，第二天运走它的(2/5)，剩下的第三天运完．第三天运走这批物资的多少．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

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

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

<result>7/20 = around 0.35</result>