Đáp án + Giải thích các bước giải:
a)
$\dfrac{3}{8}+\dfrac{6}{-18}-\dfrac{-9}{27}-\dfrac{2}{-16}$
$=\dfrac{3}{8}+\dfrac{-1}{3}-\dfrac{-1}{3}-\dfrac{-1}{13}$
$=(\dfrac{-1}{3}-\dfrac{-1}{3}) - \dfrac{3}{8}+\dfrac{-1}{13}$
$=0 - \dfrac{3}{8}+\dfrac{-1}{13}$
$=\dfrac{-3}{8}+\dfrac{-1}{13}$
$=\dfrac{-39}{104}+\dfrac{-8}{104}$
$=\dfrac{-47}{104}$
b)
$(\dfrac{13}{5}-\dfrac{7}{16}) - (\dfrac{15}{6} -\dfrac{6}{15})$
$=\dfrac{13}{5}-\dfrac{7}{16} - \dfrac{5}{2} +\dfrac{2}{5}$
$=(\dfrac{13}{5}+\dfrac{2}{5})-\dfrac{7}{16} - \dfrac{5}{2}$
$=3 - \dfrac{7}{16} - \dfrac{5}{2}$
$=\dfrac{41}{16} - \dfrac{5}{2}$
$=\dfrac{41}{16} - \dfrac{40}{16}$
$=\dfrac{1}{16}$
c)
$\dfrac{3}{17} - \dfrac{5}{13} - \dfrac{14}{-17} + \dfrac{18}{-35} - \dfrac{-8}{13} - \dfrac{7}{35}$
$=(\dfrac{3}{17}- \dfrac{14}{-17}) -(\dfrac{5}{13}- \dfrac{-8}{13}) + (\dfrac{18}{-35}- \dfrac{7}{35})$
$=1-1+\dfrac{-11}{35}$
$=0+\dfrac{-11}{35}$
$=\dfrac{-11}{35}$
