There is a rectangular piece of paper, Xiao Ming and Xiao Li each use this paper (2/7). How much of the paper did the two share?
有一张长方形纸，小明和小利各用去这张纸的(2/7)．两人一共用去了这张纸的几分之几？
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">(2/7) + (2/7)</gadget>
<output>4/7 = around 0.571429</output>

<result>4/7 = around 0.571429</result>