Given that the reciprocal of 5(3/7) is m, and the reciprocal of n is 2(3/7), find the reciprocal of m+n.
已知5(3/7)的倒数为m，n的倒数为2(3/7)，求m+n的倒数．
<gadget id="calculator">7 / 38</gadget>
<output>7/38 = around 0.184211</output>

<gadget id="calculator">7 / 17</gadget>
<output>7/17 = around 0.411765</output>

<gadget id="calculator">(7/38) + (7/17)</gadget>
<output>385/646 = around 0.595975</output>

<gadget id="calculator">1 / (385/646)</gadget>
<output>646/385 = around 1.677922</output>

<result>646/385 = around 1.677922</result>