Bài Làm:
1.
a) $\frac{5}{6}$ và $\frac{1}{4}$
$\frac{5}{6}$ = $\frac{5x2}{6x2}$ = $\frac{10}{12}$
$\frac{1}{4}$ = $\frac{1x3}{4x3}$ = $\frac{3}{12}$
b) $\frac{3}{5}$ và $\frac{3}{7}$
$\frac{3}{5}$ = $\frac{3x7}{5x7}$ = $\frac{21}{35}$
$\frac{3}{7}$ = $\frac{3x5}{7x5}$ = $\frac{15}{35}$
c) $\frac{9}{8}$ và $\frac{8}{9}$
$\frac{9}{8}$ = $\frac{9x9}{8x9}$ = $\frac{81}{72}$
$\frac{8}{9}$ = $\frac{8x8}{9x8}$ = $\frac{64}{72}$
2.
a) $\frac{7}{5}$ và $\frac{8}{11}$
$\frac{7}{5}$ = $\frac{7x11}{5x11}$ = $\frac{77}{55}$
$\frac{8}{11}$ = $\frac{8x5}{11x5}$ = $\frac{40}{55}$
b) $\frac{5}{12}$ và $\frac{3}{8}$
$\frac{5}{12}$ = $\frac{5x2}{12x2}$ = $\frac{10}{24}$
$\frac{3}{8}$ = $\frac{3x3}{8x3}$ = $\frac{9}{24}$
c) $\frac{17}{10}$ và $\frac{9}{7}$
$\frac{17}{10}$ = $\frac{17x7}{10x7}$ = $\frac{119}{70}$
$\frac{9}{7}$ = $\frac{9x10}{7x10}$ = $\frac{90}{70}$
3.
$\frac{4}{13}$ = $\frac{4x12}{13x12}$ =$\frac{48}{156}$
$\frac{5}{12}$ = $\frac{5x13}{12x13}$ =$\frac{65}{156}$
$\frac{6}{13}$ = $\frac{6x12}{12x13}$ =$\frac{72}{156}$
$\frac{7}{12}$ = $\frac{7x13}{12x13}$ =$\frac{91}{156}$