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![](https://rs.olm.vn/images/avt/0.png?1311)
a) $\frac{2}{5} \times \frac{3}{8} \times \frac{3}{4} = \frac{{2 \times 3 \times 3}}{{5 \times 8 \times 4}} = \frac{{18}}{{160}} = \frac{9}{{80}}$
b) $\frac{1}{3} \times \frac{1}{6} \times \frac{1}{9} = \frac{{1 \times 1 \times 1}}{{3 \times 6 \times 9}} = \frac{1}{{162}}$
c) $\frac{3}{4}:\frac{1}{5}:\frac{7}{8} = \frac{3}{4} \times \frac{5}{1} \times \frac{8}{7} = \frac{{3 \times 5 \times 8}}{{4 \times 1 \times 7}} = \frac{{120}}{{28}} = \frac{{30}}{7}$
d) $\frac{3}{5}:\frac{1}{5}:\frac{3}{8} = \frac{3}{5} \times \frac{5}{1} \times \frac{8}{3} = \frac{{3 \times 5 \times 8}}{{5 \times 1 \times 3}} = 8$
![](https://rs.olm.vn/images/avt/0.png?1311)
a) $\frac{3}{2} \times \frac{5}{8} + \frac{7}{4} = \frac{{15}}{{16}} + \frac{7}{4} = \frac{{15}}{{16}} + \frac{{28}}{{16}} = \frac{{43}}{{16}}$
b) $\frac{8}{5}:\left( {\frac{4}{3} - \frac{5}{6}} \right) = \frac{8}{5}:\left( {\frac{8}{6} - \frac{5}{6}} \right) = \frac{8}{5}:\frac{1}{2} = \frac{8}{5} \times 2 = \frac{{16}}{5}$
c) $\frac{3}{4} \times \frac{1}{5} - \frac{1}{{10}} = \frac{3}{{20}} - \frac{1}{{10}} = \frac{3}{{20}} - \frac{2}{{20}} = \frac{1}{{20}}$
![](https://rs.olm.vn/images/avt/0.png?1311)
a)
\(\dfrac{3}{5}\times\dfrac{7}{11}\times\dfrac{5}{3}\times11\\ =\left(\dfrac{3}{5}\times\dfrac{5}{3}\right)\times\left(\dfrac{7}{11}\times11\right)\\ =\dfrac{3\times5}{5\times3}\times\dfrac{7\times11}{11}\\ =1\times7\\ =7\)
b)
\(\dfrac{3}{8}\times\dfrac{2}{7}+\dfrac{5}{7}\times\dfrac{3}{8}\\ =\dfrac{3}{8}\times\left(\dfrac{2}{7}+\dfrac{5}{7}\right)\\ =\dfrac{3}{8}\times\dfrac{7}{7}\\ =\dfrac{3}{8}\times1=\dfrac{3}{8}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(\dfrac{2}{5}\times?=\dfrac{3}{10}\)
\(?=\dfrac{3}{10}:\dfrac{2}{5}=\dfrac{3}{4}\)
b) \(\dfrac{1}{8}:?=\dfrac{1}{5}\)
\(?=\dfrac{1}{8}:\dfrac{1}{5}=\dfrac{5}{8}\)
a: Phân số cần tìm là: \(\dfrac{3}{10}:\dfrac{2}{5}=\dfrac{3}{10}\cdot\dfrac{5}{2}=\dfrac{15}{20}=\dfrac{3}{4}\)
b: Phân số cần tìm là \(\dfrac{1}{8}:\dfrac{1}{5}=\dfrac{5}{8}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(a,\dfrac{2}{13}\times\dfrac{22}{5}\times\dfrac{13}{2}\\ =\left(\dfrac{2}{13}\times\dfrac{13}{2}\right)\times\dfrac{22}{5}\\ =1\times\dfrac{22}{5}=\dfrac{22}{5}\\ b,\dfrac{3}{5}\times\dfrac{6}{7}+\dfrac{6}{7}\times\dfrac{3}{5}\\ =\dfrac{3}{5}\times\left(\dfrac{6}{7}+\dfrac{6}{7}\right)\\ =\dfrac{3}{5}\times\dfrac{12}{7}=\dfrac{36}{35}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) $\frac{7}{2} \times \frac{1}{6} = \frac{7}{{12}}$
b) $\frac{8}{{11}} \times 4 = \frac{{32}}{{11}}$
c) $\frac{8}{9}:\frac{2}{5} = \frac{8}{9} \times \frac{5}{2} = \frac{{40}}{{18}} = \frac{{20}}{9}$
d) $\frac{5}{8}:7 = \frac{5}{8} \times \frac{1}{7} = \frac{5}{{56}}$
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(\dfrac{2}{4}\times\dfrac{9}{5}=\dfrac{1}{2}\times\dfrac{9}{5}=\dfrac{1\times9}{2\times5}=\dfrac{9}{10}\)
b) \(\dfrac{13}{8}\times\dfrac{5}{15}=\dfrac{13}{8}\times\dfrac{1}{3}=\dfrac{13}{24}\)
c) \(\dfrac{3}{9}\times\dfrac{6}{12}=\dfrac{1}{3}\times\dfrac{1}{2}=\dfrac{1}{3\times2}=\dfrac{1}{6}\)
a: =18/20=9/10
b: \(=\dfrac{13\cdot5}{8\cdot15}=\dfrac{13}{8}\cdot\dfrac{1}{3}=\dfrac{13}{24}\)
c: \(=\dfrac{1}{3}\cdot\dfrac{1}{2}=\dfrac{1}{6}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(a,?=\dfrac{5}{11}\times\dfrac{2}{7}=\dfrac{10}{77}\\ b,?=\dfrac{3}{4}:\dfrac{5}{8}=\dfrac{3}{4}\times\dfrac{8}{5}=\dfrac{6}{5}\\ c,?=1:\dfrac{6}{11}=\dfrac{11}{6}\)
a) \(?:\dfrac{2}{7}=\dfrac{5}{11}\)
\(?=\dfrac{5}{11}\times\dfrac{2}{7}\)
\(?=\dfrac{10}{77}\)
b) \(\dfrac{3}{4}:?=\dfrac{5}{8}\)
\(?=\dfrac{3}{4}:\dfrac{5}{8}\)
\(?=\dfrac{3}{4}\times\dfrac{8}{5}\)
\(?=\dfrac{6}{5}\)
c) \(?\times\dfrac{6}{11}=1\)
\(?=1:\dfrac{6}{11}\)
\(?=1\times\dfrac{11}{6}\)
\(?=\dfrac{11}{6}\)
a. 35 / 6
b. 32 / 45
c. 8 / 11
d. 2 / 7
a) \(\dfrac{4}{3}\) x \(\dfrac{7}{8}\) x 5
= \(\dfrac{7}{6}\) x 5
= \(\dfrac{35}{6}\)
b) \(\dfrac{8}{9}x\dfrac{6}{5}:\dfrac{3}{2}\)
= \(\dfrac{16}{15}:\dfrac{3}{2}\)
= \(\dfrac{32}{45}\)
c) \(\dfrac{4}{7}:\dfrac{5}{7}x\dfrac{10}{11}\)
= \(\dfrac{4}{5}x\dfrac{10}{11}\)
= \(\dfrac{8}{11}\)