Đáp án:
Giải thích các bước giải:
$A$ = $\dfrac{1}{3.8}$ + $\dfrac{1}{6.12}$ + $\dfrac{1}{9.16}$ ... + $\dfrac{1}{1512.2020}$
$A$ = $\dfrac{1}{5}$ x ( $\dfrac{1}{3}$-$\dfrac{1}{8}$ + $\dfrac{1}{6}$ - $\dfrac{1}{12}$ + ... + $\dfrac{1}{1512}$ - $\dfrac{1}{2020}$ )
$A$ = $\dfrac{1}{5}$ x ( $\dfrac{1}{3}$ - $\dfrac{1}{2020}$ )
$A$ = $\dfrac{1}{5}$ x $\dfrac{2017}{6060}$
$A$ = $\dfrac{2017}{30300}$
