Cho M= ( 21/ 31+ -16/7) + ( 44/53+ 10/31) + 9/53 và

* Hướng dẫn giải

$M=\left(\frac{21}{31}+\frac{-16}{7}\right)+\left(\frac{44}{53}+\frac{10}{31}\right)+\frac{9}{53}$

$M=\frac{21}{31}+\frac{-16}{7}+\frac{44}{53}+\frac{10}{31}+\frac{9}{53}$

$M=\left(\frac{21}{31}+\frac{10}{31}\right)+\left(\frac{44}{53}+\frac{9}{53}\right)+\frac{-16}{7}$

$M=1+1+\frac{-16}{7}$

$M=2+\frac{-16}{7}$

$M=\frac{-2}{7}$

$N=\frac{1}{2}+\frac{-1}{5}+\frac{-5}{7}+\frac{1}{6}+\frac{-3}{35}+\frac{1}{3}+\frac{1}{41}$

$N=\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{3}\right)+\left(\frac{-1}{5}+\frac{-5}{7}+\frac{-3}{35}\right)+\frac{1}{41}$

$N=\frac{3+1+2}{6}+\frac{\left(-7\right)+\left(-25\right)+\left(-3\right)}{35}+\frac{1}{41}$

$N=1+\left(-1\right)+\frac{1}{41}$

$N=\frac{1}{41}$