$\frac{7}{9}$ и $\frac{5}{6}$
$\frac{7}{9}=\frac{2}{18}$
$\frac{5}{6}=\frac{15}{18}$
$\frac{2}{18}<\frac{15}{18}$, значит $\frac{7}{9}<\frac{5}{6}$.

$\frac{11}{16}$ и $\frac{7}{12}$
$\frac{11}{16}=\frac{33}{48}$
$\frac{7}{12}=\frac{28}{48}$
$\frac{33}{48}>\frac{28}{48}$, значит $\frac{11}{16}>\frac{7}{12}$.

$\frac{5}{16}$ и $\frac{3}{8}$
$\frac{3}{8}=\frac{6}{16}$
$\frac{5}{16}<\frac{6}{16}$, значит $\frac{5}{16}<\frac{3}{8}$.

$\frac{8}{11}$ и $\frac{3}{4}$
$\frac{8}{11}=\frac{32}{44}$
$\frac{3}{4}=\frac{33}{44}$
$\frac{32}{44}<\frac{33}{44}$, значит $\frac{8}{11}<\frac{3}{4}$.

$\frac{19}{21}$ и $\frac{5}{6}$
$\frac{19}{21}=\frac{38}{42}$
$\frac{5}{6}=\frac{35}{42}$
$\frac{38}{42}>\frac{35}{42}$, значит $\frac{19}{21}>\frac{5}{6}$.

$\frac{9}{25}$ и $\frac{7}{20}$
$\frac{9}{25}=\frac{36}{100}$
$\frac{7}{20}=\frac{35}{100}$
$\frac{36}{100}>\frac{35}{100}$, значит $\frac{9}{25}>\frac{7}{20}$.