2/3 ... 11/18

a) $\frac{2}{3}$> $\frac{11}{18}$

   b) $\frac{36}{63}$ < $\frac{5}{7}$

   c) $\frac{55}{110}$= $\frac{4}{8}$

a) $\frac{2}{3}=\frac{2\times 6}{3\times 6}=\frac{12}{18}$

Vì $\frac{12}{18}$ > $\frac{11}{18}$ nên $\frac{2}{3}$> $\frac{11}{18}$

b)$\frac{36}{63}=\frac{36:9}{63:9}=\frac{4}{7}$

Vì $\frac{4}{7}$ < $\frac{5}{7}$ nên $\frac{36}{63}$< $\frac{5}{7}$

c) $\frac{55}{110}$ = $\frac{55:55}{110:55}$ = $\frac{1}{2}$

$\frac{4}{8}$ = $\frac{4:4}{8:4}$ = $\frac{1}{2}$

Vì $\frac{1}{2}$ = $\frac{1}{2}$ nên $\frac{55}{110}$= $\frac{4}{8}$