Bài Làm:
1.
|
a) $\frac{2}{7}$ : $\frac{4}{5}$ = $\frac{5}{14}$ c) $\frac{8}{21}$ : $\frac{4}{7}$ = $\frac{2}{3}$ |
b) $\frac{3}{8}$ : $\frac{9}{4}$ = $\frac{1}{6}$ d) $\frac{5}{8}$ : $\frac{15}{8}$ = $\frac{1}{3}$ |
2.
a) 3 : $\frac{5}{7}$ = $\frac{21}{5}$
b) 4 : $\frac{1}{3}$ = 12
c) 5 : $\frac{1}{6}$ = 30
3.
a) ($\frac{2}{3}$ + $\frac{1}{4}$) x $\frac{3}{2}$ = ?
Cách 1: $\frac{11}{12}$ x $\frac{3}{2}$ = $\frac{11}{8}$
Cách 2: $\frac{2}{3}$ x $\frac{3}{2}$ + $\frac{1}{4}$ x $\frac{3}{2}$
= 1 + $\frac{3}{2}$ = $\frac{5}{2}$
b) ($\frac{5}{6}$ - $\frac{2}{3}$) x $\frac{6}{5}$ = ?
Cách 1: $\frac{5}{6}$ x $\frac{6}{5}$ - $\frac{2}{3}$ x $\frac{6}{5}$ = $\frac{1}{5}$
Cách 2: $\frac{1}{6}$ x $\frac{6}{5}$ = $\frac{1}{5}$
4.
$\frac{1}{3}$ : $\frac{1}{12}$ = $\frac{1}{3}$ x $\frac{12}{1}$ = 4. Vậy $\frac{1}{3}$ gấp 4 lần $\frac{1}{12}$.
$\frac{1}{4}$ : $\frac{1}{12}$ = $\frac{1}{4}$ x $\frac{12}{1}$ = 3. Vậy $\frac{1}{4}$ gấp 3 lần $\frac{1}{12}$.
5.
C. $\frac{9}{8}$.