giúp mình bài 1 với, cảm ơn

$xin$ ${CTLHN}$ $ạ$

a, 

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

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

=$\frac{31}{31}$+$\frac{53}{53}$+$\frac{-16}{7}$

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

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

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

b,

=($\frac{10}{8}$ + $\frac{5}{10}$ ) x ($\frac{-5}{13}$)

=$\frac{10}{13}$ x $\frac{-5}{3}$

=$\frac{-1}{2}$

c, 

=$\frac{5}{7}$ x ($\frac{2}{11}$ + $\frac{5}{11}$ - $\frac{14}{11}$)

=$\frac{5}{7}$ x ($\frac{7}{11}$ - $\frac{14}{11}$)

=$\frac{5}{7}$ x $\frac{-7}{11}$

= $\frac{-5}{11}$ 

d,

=($\frac{1}{37}$ + $\frac{1}{43}$ - $\frac{15}{131}$ ) x ($\frac{5}{6}$ -$\frac{2}{6}$ -$\frac{1}{6}$)

= $-0,06$ x $\frac{1}{3}$ ( ở -0,06 có rút gọn số vì quá dài)

==$\frac{-1}{50}$