((x)/2) and ((y)/7) are two simplest fractions respectively, the sum of these two fractions is (13/14), then x+y=how much.
((x)/2)和((y)/7)分别是两个最简分数，这两个分数的和是(13/14)，那么x+y=多少．
<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<result>4</result>