Toán Lớp 7: a, $\frac{10}{17}$ – $\frac{5}{13}$ -$\frac{7}{12}$ -$\frac{8}{13}$ + $\frac{-11}{15}$ b, $\frac{3}{5}$ +$\frac{3}{11}$ -$\frac{-3}

Toán Lớp 7: a, $\frac{10}{17}$ – $\frac{5}{13}$ -$\frac{7}{12}$ -$\frac{8}{13}$ + $\frac{-11}{15}$
b, $\frac{3}{5}$ +$\frac{3}{11}$ -$\frac{-3}{7}$ +$\frac{-2}{97}$ + $\frac{1}{-35}$ – $\frac{3}{4}$ + $\frac{-23}{44}$
c , $\frac{1}{3}$ – $\frac{1}{4}$ – ( $\frac{3}{-5}$ ) + $\frac{1}{72}$ – $\frac{2}{9}$ – $\frac{1}{36}$ + $\frac{1}{15}$