giúp mình với ajjjjjjjj

Đáp án:

a) $\dfrac{-11}{20}$;

b) $\dfrac{5}{6}$;

c) $\dfrac{109}{9}$;

d) $\dfrac{37}{24}$.

Giải thích các bước giải:

a) $\dfrac{-10}{13}$ + $\dfrac{5}{17}$ - $\dfrac{3}{13}$ + $\dfrac{12}{17}$ - $\dfrac{11}{20}$

`=` ($\dfrac{-10}{13}$ - $\dfrac{3}{13}$) + ($\dfrac{5}{17}$ + $\dfrac{12}{17}$) - $\dfrac{11}{20}$

`=` ($\dfrac{-13}{13}$) + ($\dfrac{17}{17}$) - $\dfrac{11}{20}$

`= -1 + 1` - $\dfrac{11}{20}$

`= 0` - $\dfrac{11}{20}$

`=` $\dfrac{-11}{20}$.

b) $\dfrac{3}{4}$ + $\dfrac{-5}{6}$ - $\dfrac{11}{-12}$

`=` $\dfrac{3}{4}$ + $\dfrac{-5}{6}$ + $\dfrac{11}{12}$

`=` $\dfrac{9}{12}$ + $\dfrac{-10}{12}$ + $\dfrac{11}{12}$

`=` $\dfrac{9 + (-10) + 11}{12}$

`=` $\dfrac{10}{12}$

`=` $\dfrac{5}{6}$.

c) $\text{(13$\dfrac{4}{9}$ + 2$\dfrac{1}{9}$) - 3$\dfrac{4}{9}$}$

`=` ($\dfrac{121}{9}$ + $\dfrac{19}{9}$) - $\dfrac{31}{9}$

`=` $\dfrac{140}{9}$ - $\dfrac{31}{9}$

`=` $\dfrac{109}{9}$.

d) $\text{1,25 : $\dfrac{15}{20}$ + (25% - $\dfrac{5}{6}$) : 4$\dfrac{2}{3}$}$

`=` $\text{$\dfrac{5}{4}$ : $\dfrac{3}{4}$ + ($\dfrac{1}{4}$ - $\dfrac{5}{6}$) : $\dfrac{14}{3}$}$

`=` $\text{$\dfrac{5}{4}$ : $\dfrac{3}{4}$ + $\dfrac{-7}{12}$ : $\dfrac{14}{3}$}$

`=` $\text{$\dfrac{5}{4}$ . $\dfrac{4}{3}$ + $\dfrac{-7}{12}$ . $\dfrac{3}{14}$}$

`=` $\dfrac{5}{3}$ + $\dfrac{-1}{8}$

`=` $\dfrac{37}{24}$.

$#kannekkk$