We see that:

\(\dfrac{1}{5.9}\)=\(\dfrac{1}{4}\). \(\dfrac{4}{5.9}\)=\(\dfrac{1}{4}\). \(\dfrac{1}{5}\)- \(\dfrac{1}{9}\)

=>A=\(\dfrac{1}{4}\). \(\dfrac{1}{5}\)- \(\dfrac{1}{9}\)+ \(\dfrac{1}{9}\)- \(\dfrac{1}{13}\)+...+\(\dfrac{1}{161}\)- \(\dfrac{1}{165}\)

       =\(\dfrac{1}{4}\). \(\dfrac{1}{5}\)- \(\dfrac{1}{165}\)

       =\(\dfrac{8}{165}\)

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