So sánh:
$\frac{3}{4}$= $\frac{3*5}{4*5}$= $\frac{15}{20}$
$\frac{3}{5}$= $\frac{3*4}{5*4}$= $\frac{12}{20}$
Mà $\frac{15}{20}$> $\frac{12}{20}$
=> $\frac{3}{4}$>$\frac{3}{5}$
$\frac{1}{8}$= $\frac{1*9}{8*9}$ =$\frac{9}{72}$
$\frac{1}{9}$= $\frac{1*8}{9*8}$ =$\frac{8}{72}$
Mà $\frac{9}{72}$ > $\frac{8}{72}$
=> $\frac{1}{8}$ > $\frac{1}{9}$
Xin hay nhất ạ.