Bài Làm:
1.
$\frac{1}{6}$ và $\frac{4}{5}$
$\frac{1}{6}$ = $\frac{1x5}{6x5}$ = $\frac{5}{30}$
$\frac{4}{5}$ = $\frac{4x6}{5x6}$ = $\frac{24}{30}$
$\frac{11}{49}$ và $\frac{8}{7}$
$\frac{11}{49}$
$\frac{8}{7}$ = $\frac{8x7}{7x7}$ = $\frac{56}{49}$
$\frac{12}{5}$ và $\frac{5}{9}$
$\frac{12}{5}$ = $\frac{12x9}{5x9}$ = $\frac{108}{45}$
$\frac{5}{9}$ = $\frac{5x5}{9x5}$ = $\frac{25}{45}$
b)
$\frac{5}{9}$ và $\frac{7}{36}$
$\frac{5}{9}$ = $\frac{5x4}{9x4}$ = $\frac{20}{36}$
$\frac{7}{36}$
$\frac{47}{100}$ và $\frac{17}{25}$
$\frac{47}{100}$
$\frac{17}{25}$ = $\frac{17x4}{25x4}$ = $\frac{68}{100}$
2.
$\frac{3}{5}$ = $\frac{1}{5}$ + $\frac{2}{5}$
3.
$\frac{7}{12}$ = $\frac{7x5}{12x5}$ = $\frac{35}{60}$
$\frac{23}{30}$ = $\frac{23x2}{30x2}$ = $\frac{46}{60}$
4.
a) $\frac{1}{3}$; $\frac{1}{4}$ và $\frac{4}{5}$
$\frac{1}{3}$ = $\frac{1x10}{3x10}$ = $\frac{10}{30}$
$\frac{1}{4}$ = $\frac{1x10}{4x10}$ = $\frac{10}{40}$
$\frac{4}{5}$ = $\frac{4x6}{5x6}$ = $\frac{24}{30}$
b) $\frac{1}{2}$; $\frac{2}{3}$ và $\frac{3}{4}$
$\frac{1}{2}$ = $\frac{1x6}{2x6}$ = $\frac{6}{12}$
$\frac{2}{3}$ = $\frac{2x4}{3x4}$ = $\frac{8}{12}$
$\frac{3}{4}$ = $\frac{3x3}{4x3}$ = $\frac{9}{12}$
5.
a) $\frac{4 x 5 x 6}{12 x 15 x 9}$ = $\frac{2}{27}$
b) $\frac{6 x 8 x 11}{33 x 16}$ = 1