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29 tháng 10 2023

a: \(\dfrac{5}{6}\cdot7=\dfrac{5\cdot7}{6}=\dfrac{35}{6}\)

b: \(\dfrac{7}{10}\cdot3=\dfrac{7\cdot3}{10}=\dfrac{21}{10}\)

c: \(5\cdot\dfrac{4}{21}=\dfrac{5\cdot4}{21}=\dfrac{20}{21}\)

d: \(2\cdot\dfrac{5}{9}=\dfrac{2\cdot5}{9}=\dfrac{10}{9}\)

24 tháng 8 2023

a) \(\dfrac{9}{11}\times8=\dfrac{9\times8}{11}=\dfrac{72}{11}\)

b) \(\dfrac{4}{5}\times1=\dfrac{4\times1}{5}=\dfrac{4}{5}\)

c) \(\dfrac{15}{8}\times0=\dfrac{15\times0}{8}=\dfrac{0}{8}=0\)

a: 9/11*8=(9*8)/11=72/11

b: 4/5*1=(4*1)/5=4/5

c: 15/8*0=(15*0)/8=0/8=0

24 tháng 8 2023

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 \(\dfrac{1}{8}:\dfrac{1}{5}=\dfrac{5}{8}\)

23 tháng 8 2023

a) = \(\dfrac{12}{17}\)

b) = \(\dfrac{31}{37}\)

24 tháng 8 2023

a) \(3\times\dfrac{4}{11}=\dfrac{3\times4}{11}=\dfrac{12}{11}\)

b) \(1\times\dfrac{5}{4}=\dfrac{1\times5}{4}=\dfrac{5}{4}\)

c) \(0\times\dfrac{2}{5}=\dfrac{0\times2}{5}=\dfrac{0}{5}=0\)

a: \(=\dfrac{3\cdot4}{11}=\dfrac{12}{11}\)

b: \(=\dfrac{1\cdot5}{4}=\dfrac{5}{4}\)

c: \(=\dfrac{0\cdot2}{5}=0\)

24 tháng 8 2023

\(a)\dfrac{5}{7}\times\dfrac{7}{15}\\ =\dfrac{5\times7}{7\times15}\\ =\dfrac{35}{105}=\dfrac{1}{3}\\ b)\dfrac{8}{21}\times3\\ =\dfrac{8\times3}{21}\\ =\dfrac{24}{21}=\dfrac{8}{7}\\ c)\dfrac{24}{17}:\dfrac{9}{17}\\ =\dfrac{24}{17}\times\dfrac{17}{9}\\ =\dfrac{24\times17}{17\times9}\\ =\dfrac{408}{153}=\dfrac{8}{3}\\ d)\dfrac{36}{5}:9\\ =\dfrac{36}{5}\times\dfrac{1}{9}\\ =\dfrac{36\times1}{5\times9}\\ =\dfrac{36}{45}=\dfrac{4}{5}\)

24 tháng 8 2023

a) \(\dfrac{5}{7}\times\dfrac{7}{15}=\dfrac{5\times7}{7\times15}=\dfrac{35}{105}=\dfrac{1}{3}\)

b) \(\dfrac{8}{21}\times3=\dfrac{8\times3}{21}=\dfrac{24}{21}=\dfrac{8}{7}\)

c) \(\dfrac{24}{17}:\dfrac{9}{17}=\dfrac{24}{17}\times\dfrac{17}{9}=\dfrac{24\times17}{17\times9}=\dfrac{24}{9}=\dfrac{8}{3}\)

d) \(\dfrac{36}{5}:9=\dfrac{36}{5}\times\dfrac{1}{9}=\dfrac{36}{5\times9}=\dfrac{36}{45}=\dfrac{4}{5}\)

29 tháng 10 2023

a: \(\dfrac{3}{9}\times\dfrac{5}{4}=\dfrac{5}{4}\times\dfrac{1}{3}=\dfrac{5\times1}{4\times3}=\dfrac{5}{12}\)

b: \(\dfrac{10}{15}\times\dfrac{3}{5}=\dfrac{3}{5}\times\dfrac{2}{3}=\dfrac{3\times2}{5\times3}=\dfrac{2}{5}\)

c: \(\dfrac{5}{8}\times\dfrac{4}{12}=\dfrac{5}{8}\times\dfrac{1}{3}=\dfrac{5}{3\times8}=\dfrac{5}{24}\)

d: \(\dfrac{9}{27}\times\dfrac{3}{21}=\dfrac{1}{7}\times\dfrac{1}{3}=\dfrac{1\times1}{7\times3}=\dfrac{1}{21}\)

11 tháng 2 2022

\(=\dfrac{4}{7}\)

HQ
Hà Quang Minh
Giáo viên
27 tháng 11 2023

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) $\frac{3}{5}:\frac{1}{5}:\frac{3}{8} = \frac{3}{5} \times \frac{5}{1} \times \frac{8}{3} = \frac{{3 \times 5 \times 8}}{{5 \times 1 \times 3}} = 8$

HQ
Hà Quang Minh
Giáo viên
27 tháng 11 2023

a)  $\frac{3}{5} \times \frac{6}{7} = \frac{{3 \times 6}}{{5 \times 7}} = \frac{{18}}{{35}}$                                                 

 b) $\frac{2}{9} \times \frac{{18}}{3} = \frac{{2 \times 18}}{{9 \times 3}} = \frac{{36}}{{27}} = \frac{4}{3}$

c)  $\frac{5}{7} \times 12 = \frac{{5 \times 12}}{7} = \frac{{60}}{7}$                                            

d)  $21 \times \frac{2}{7} = \frac{{21 \times 2}}{7} = \frac{{42}}{7} = 6$