\(a,\dfrac{13}{4}\times\dfrac{2}{3}\times\dfrac{4}{13}\times\dfrac{3}{2}=\left(\dfrac{13}{4}\times\dfrac{4}{3}\right)\times\left(\dfrac{2}{3}\times\dfrac{3}{2}\right)=1\times1=1\)
\(b,\dfrac{75}{100}+\dfrac{18}{21}+\dfrac{19}{32}+\dfrac{1}{4}+\dfrac{3}{21}+\dfrac{13}{32}=\left(\dfrac{3}{4}+\dfrac{1}{4}\right)+\left(\dfrac{18}{21}+\dfrac{3}{21}\right)+\left(\dfrac{19}{32}+\dfrac{13}{32}\right)=1+1+1=3\\ c,\dfrac{4}{7}\times\dfrac{5}{6}+\dfrac{4}{7}\times\dfrac{1}{6}=\dfrac{4}{7}\times\left(\dfrac{5}{6}+\dfrac{1}{6}\right)=\dfrac{4}{7}\times1=\dfrac{4}{7}\\ d,\dfrac{3}{5}\times\dfrac{7}{9}-\dfrac{3}{5}\times\dfrac{2}{9}=\dfrac{3}{5}\times\left(\dfrac{7}{9}-\dfrac{2}{9}\right)=\dfrac{3}{5}\times\dfrac{5}{9}=\dfrac{1}{3}\)
\(e,\dfrac{5}{9}\times\dfrac{1}{4}+\dfrac{4}{9}\times\dfrac{3}{12}=\dfrac{5}{9}\times\dfrac{1}{4}+\dfrac{4}{9}\times\dfrac{1}{4}=\dfrac{1}{4}\times\left(\dfrac{5}{9}+\dfrac{4}{9}\right)=\dfrac{1}{4}\times1=\dfrac{1}{4}\\ f,\dfrac{7}{9}\times\dfrac{8}{5}\times\dfrac{3}{5}=\dfrac{56}{75}\\ g,\dfrac{2}{5}\times\dfrac{3}{4}+\dfrac{3}{4}\times\dfrac{3}{5}=\dfrac{3}{4}\times\left(\dfrac{2}{5}+\dfrac{3}{5}\right)=\dfrac{3}{4}\times1=\dfrac{3}{4}\\ h,\dfrac{2006}{2005}\times\dfrac{3}{4}-\dfrac{3}{4}\times\dfrac{1}{2005}=\dfrac{3}{4}\times\left(\dfrac{2006}{2005}-\dfrac{1}{2005}\right)=\dfrac{3}{4}\times1=\dfrac{3}{4}\)
a: \(=\dfrac{13}{4}\cdot\dfrac{4}{13}\cdot\dfrac{2}{3}\cdot\dfrac{3}{2}=1\cdot1=1\)
b: \(=\dfrac{3}{4}+\dfrac{1}{4}+\dfrac{6}{7}+\dfrac{1}{7}+\dfrac{19}{32}+\dfrac{13}{32}=1+1+1=3\)
c: \(=\dfrac{4}{7}\left(\dfrac{5}{6}+\dfrac{1}{6}\right)=\dfrac{4}{7}\)
d: \(=\dfrac{3}{5}\left(\dfrac{7}{9}-\dfrac{2}{9}\right)=\dfrac{3}{5}\cdot\dfrac{5}{9}=\dfrac{1}{3}\)
e: \(=\dfrac{1}{4}\left(\dfrac{5}{9}+\dfrac{4}{9}\right)=\dfrac{1}{4}\)
Giúp mình bì này nha mình đang cần gấp cảm ơn các bạn 
