1/2 + -1/5 + -5/7 + 1/6 + -3/35 + 1/3 +1/41

Đáp án:

$\dfrac{1}{41}$

Giải thích các bước giải:

$\dfrac{1}{2}+\dfrac{-1}{5}+\dfrac{-5}{7}+\dfrac{1}{6}+\dfrac{-3}{35}+\dfrac{1}{3}+\dfrac{1}{41}$

$=\dfrac{1}{2}-\dfrac{1}{5}-\dfrac{5}{7}+\dfrac{1}{6}-\dfrac{3}{35}+\dfrac{1}{3}+\dfrac{1}{41}$

$=\left(\dfrac{1}{2}-\dfrac{1}{5}-\dfrac{5}{7}\right)+\left(\dfrac{1}{6}-\dfrac{3}{35}\right)+\left(\dfrac{1}{3}+\dfrac{1}{41}\right)$

$=-\dfrac{29}{70}+\dfrac{17}{210}+\dfrac{44}{123}$

$=\dfrac{1}{41}$