a) \(\frac{3}{5}+\frac{6}{11}+\frac{7}{13}+\frac{5}{11}+\frac{2}{5}+\frac{19}{13}=\left(\frac{3}{5}+\frac{2}{5}\right)+\left(\frac{6}{11}+\frac{5}{11}\right)+\left(\frac{7}{13}+\frac{19}{13}\right)=1+1+2=4\)

b) \(\frac{6}{5}\times\frac{3}{8}+\frac{5}{8}\times\frac{6}{5}-\frac{4}{5}=\frac{6}{5}\times\left(\frac{3}{8}+\frac{5}{8}\right)-\frac{4}{5}=\frac{6}{5}-\frac{4}{5}=\frac{2}{5}\)

c) \(\frac{4\times5\times6\times7\times8}{8\times10\times12\times14\times16}=\frac{1}{2\times2\times2\times2\times2}=\frac{1}{32}\)

a, \(\frac{3}{5}+\frac{6}{11}+\frac{7}{13}+\frac{6}{11}+\frac{2}{5}+\frac{19}{13}\)

\(=\left(\frac{3}{5}+\frac{2}{5}\right)+\left(\frac{7}{13}+\frac{19}{13}\right)+\left(\frac{6}{11}+\frac{6}{11}\right)\)

\(=1+2+\frac{12}{11}\)

\(=3+\frac{12}{11}\)

\(=\frac{45}{11}\)

Bằng 45/11 bạn nhé

Chúc bạn học giỏi 

\(a)\frac{3}{5}+\frac{6}{11}+\frac{7}{13}+\frac{6}{11}+\frac{2}{5}+\frac{19}{13}\)

\(=\frac{3}{5}+\frac{2}{5}+\frac{6}{11}+\frac{6}{11}+\frac{7}{13}+\frac{19}{13}\)

\(=1+\frac{12}{11}+2\)

\(=\frac{11}{11}+\frac{12}{11}+\frac{22}{11}\)

\(=\frac{45}{11}\)

\(b)\frac{6}{5}.\frac{3}{8}+\frac{5}{8}.\frac{6}{5}-\frac{4}{5}\)

\(=\frac{6}{5}\left(\frac{3}{8}+\frac{5}{8}\right)-\frac{4}{5}\)

\(=\frac{6}{5}-\frac{4}{5}=\frac{2}{5}\)

\(c)\frac{4.5.6.7.8}{8.10.12.14.16}\)

\(=\frac{4.5.6.7.8}{2.4.2.5.2.6.2.7.2.8}\)

\(=\frac{1}{2.2.2.2.2}\)

\(=\frac{1}{2^5}=\frac{1}{32}\)

haha