A batch of goods, its (2/7) was shipped out for the first time, and its (5/7) was shipped out for the second time, how much was shipped in total? What fraction is left?
一批货，第一次运走它的(2/7)，第二次运走它的(5/7)，两次一共运走多少？还剩下几分之几？
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">(2/7) + (5/7)</gadget>
<output>1</output>

<result>1</result>