Đáp án:
A) $\dfrac{1}{3}$
B) $\dfrac{14}{11}$
Giải thích các bước giải:
a)
$(\dfrac{1}{3} + \dfrac{12}{67} + \dfrac{13}{41}) - (\dfrac{79}{67} - \dfrac{28}{41})$
$=\dfrac{1}{3} + \dfrac{12}{67} + \dfrac{13}{41} - \dfrac{79}{67} + \dfrac{28}{41}$
$=(\dfrac{13}{41} + \dfrac{28}{41}) + (\dfrac{12}{67} - \dfrac{79}{67}) + \dfrac{1}{3}$
$= 1 + (-1) + \dfrac{1}{3}$
$= 0 + \dfrac{1}{3}$
$= \dfrac{1}{3}$
b)
$\dfrac{38}{45} - (\dfrac{8}{45} - \dfrac{17}{51} - \dfrac{3}{11})$
$=\dfrac{38}{45} - \dfrac{8}{45} + \dfrac{17}{51} + \dfrac{3}{11}$
$=\dfrac{30}{45} + (\dfrac{17}{51} - \dfrac{3}{11})$
$=\dfrac{2}{3} + \dfrac{17}{51} + \dfrac{3}{11}$
$=\dfrac{34}{51} + \dfrac{17}{51} + \dfrac{3}{11}$
$= 1 + \dfrac{3}{11}$
$= \dfrac{14}{11}$
