Thực hiện phép tính a) -5/7 + 7/13 + -9/17 + 2/-7 + 6/13 b) 29 4/7

* Hướng dẫn giải

a) $\frac{-5}{7}+\frac{7}{13}+\frac{-9}{17}+\frac{2}{-7}+\frac{6}{13}$$=\left(\frac{-5}{7}+\frac{-2}{7}\right)+\left(\frac{7}{13}+\frac{6}{13}\right)+\frac{-9}{17}$$=-1+1+\frac{-9}{17}=\frac{-9}{17}$

b) $29\frac{4}{11}-\left(3\frac{7}{13}+25\frac{4}{11}\right)$$=\left(29\frac{4}{11}-25\frac{4}{11}\right)-3\frac{7}{13}=4-3\frac{7}{13}$$=3\frac{13}{13}-3\frac{7}{13}=\frac{6}{13}$