Đáp án:

Giải thích các bước giải:

 $ A= \dfrac{1}{4}$+$\dfrac{1}{9}$+....+$\dfrac{1}{529}$

 $A = \dfrac{1}{2\times2}$+$\dfrac{1}{3\times3}$+...+$\dfrac{1}{23\times23}$ 

$ A < B = \dfrac{1}{1\times2}$+$\dfrac{1}{2\times3}$+...+$\dfrac{1}{22\times23}$ 

$B=\dfrac{1}{1\times2}$+$\dfrac{1}{2\times3}$+...+$\dfrac{1}{22\times23}$ 

$B=\dfrac{1}{1}$-$\dfrac{1}{2}$+$\dfrac{1}{2}$-$\dfrac{1}{3}$+$\dfrac{1}{3}$-$\dfrac{1}{4}$+...+$\dfrac{1}{22}$ - $\dfrac{1}{23}$

$B=\dfrac{1}{1}$- $\dfrac{1}{23}$

$B=\dfrac{22}{23}$