Calculate three fractions: (1/7)+(1/11), (1/5)+(1/13), (1/3)+(1/15). After arranging from small to large, what is the second formula?
把三个分数算式：(1/7)+(1/11)，(1/5)+(1/13)，(1/3)+(1/15)．从小到大排列后，第2个算式为多少．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 13</gadget>
<output>1/13 = around 0.076923</output>

<gadget id="calculator">(1/5) + (1/13)</gadget>
<output>18/65 = around 0.276923</output>

<result>18/65 = around 0.276923</result>