Cho M= ( 1/3+ 12/67+ 13/41) -( 79/67- 28/41) và

* Hướng dẫn giải

$M=\left(\frac{1}{3}+\frac{12}{67}+\frac{13}{41}\right)-\left(\frac{79}{67}-\frac{28}{41}\right)$

$M=\frac{1}{3}+\frac{12}{67}+\frac{13}{41}-\frac{79}{67}+\frac{28}{41}$

$M=\frac{1}{3}+\left(\frac{12}{67}-\frac{79}{67}\right)+\left(\frac{13}{41}+\frac{28}{41}\right)$

$M=\frac{1}{3}+\left(-1\right)+1$

$M=\frac{1}{3}$

$N=\frac{38}{45}-\left(\frac{8}{45}-\frac{17}{51}-\frac{3}{11}\right)$

$N=\frac{38}{45}-\frac{8}{45}+\frac{17}{51}+\frac{3}{11}$

$N=\left(\frac{38}{45}-\frac{8}{45}\right)+\frac{17}{51}+\frac{3}{11}$

$N=\frac{2}{3}+\frac{1}{3}+\frac{3}{11}$

$N=1+\frac{3}{11}$

$N=\frac{14}{11}$