Đáp án+Giải thích các bước giải:

 $a)$ $\dfrac{-3}{8}$ + $\dfrac{5}{8}$

= $\dfrac{-3 + 5}{8}$

= $\dfrac{2}{8}$

= $\dfrac{1}{4}$

$b$) $\dfrac{-4}{-5}$ + $\dfrac{2}{-5}$

= $\dfrac{4}{5}$ - $\dfrac{2}{5}$ 

= $\dfrac{4 - 2}{5}$

= $\dfrac{2}{5}$

$c)$ $\dfrac{-5}{6}$ + $\dfrac{3}{5}$

= $\dfrac{-25}{30}$ + $\dfrac{18}{30}$

= $\dfrac{-25 + 18}{30}$

= $\dfrac{-7}{30}$

$d)$ $\dfrac{-7}{16}$ - $\dfrac{13}{16}$

= $\dfrac{-7 - 13}{16}$

= $\dfrac{-20}{16}$

= $\dfrac{-5}{4}$

$e)$ $\dfrac{5}{24}$ - $\dfrac{7}{8}$

= $\dfrac{5}{24}$ - $\dfrac{21}{24}$

= $\dfrac{5 - 21}{24}$

= $\dfrac{-16}{24}$

= $\dfrac{-2}{3}$

$g)$ $\dfrac{-4}{3}$ - $\dfrac{12}{5}$

= $\dfrac{-20}{15}$ - $\dfrac{36}{15}$

= $\dfrac{-20 - 36}{15}$

= $\dfrac{-56}{15}$

h) $\dfrac{-11}{12}$ $-(1)$

= $\dfrac{-11}{12}$ + $1$

= $\dfrac{-11}{12}$ + $\dfrac{12}{12}$

= $\dfrac{-11 + 12}{12}$

= $\dfrac{1}{12}$

$k)$ $\dfrac{-18}{24}$ - $\dfrac{15}{21}$

= $\dfrac{-3}{4}$ - $\dfrac{5}{7}$

= $\dfrac{-21}{28}$ - $\dfrac{20}{28}$

= $\dfrac{-21 - 20}{28}$

= $\dfrac{-41}{28}$

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