For a batch of goods, all (2/7) were shipped on the first day, and all (3/7) were shipped on the second day. How much of this batch of goods is still not shipped?
一批货物，第一天运走了全部的(2/7)，第二天运走了全部的(3/7)，这批货物还剩多少没有运完？
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">1 - (2/7) - (3/7)</gadget>
<output>2/7 = around 0.285714</output>

<result>2/7 = around 0.285714</result>