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2 tháng 4

    \(\dfrac{3}{8}\) : \(\dfrac{9}{4}\) : 2

=  \(\dfrac{3}{8}\) x \(\dfrac{4}{9}\) x \(\dfrac{1}{2}\)

=  \(\dfrac{3\times4\times1}{4\times2\times3\times3\times2}\)

\(\dfrac{1}{12}\)

2 tháng 4

3/8:9/4:2=3/8x4/9x2=24/72=1/3

21/15+3/5-4/5=7/5+3/5-4/5=6/5

a: =1/8-1/8+2/5=2/5

b: =(-1/15-14/15)+(23/27+31/27)=2-1=1

c: \(=\dfrac{3}{7}\left(\dfrac{22}{21}+\dfrac{5}{21}+\dfrac{15}{21}\right)=\dfrac{3}{7}\cdot2=\dfrac{6}{7}\)

d: \(=\dfrac{-8}{9}\cdot\dfrac{3}{2}+\dfrac{1}{9}\cdot\dfrac{-3}{2}=-\dfrac{3}{2}\)

18 tháng 4 2020

Ghi đầy đủ nha

6 tháng 3 2022

bn có thể ghi rõ ràng đc ko?

\(\dfrac{2}{7}:\dfrac{4}{5}=\dfrac{2}{7}\cdot\dfrac{5}{4}=\dfrac{10}{28}=\dfrac{5}{14}\)

\(\dfrac{3}{8}:\dfrac{9}{4}=\dfrac{3}{8}\cdot\dfrac{4}{9}=\dfrac{12}{72}=\dfrac{1}{6}\)

\(\dfrac{8}{21}:\dfrac{4}{7}=\dfrac{8}{21}\cdot\dfrac{7}{4}=\dfrac{2}{3}\)

\(\dfrac{5}{8}:\dfrac{15}{8}=\dfrac{5}{8}\cdot\dfrac{8}{15}=\dfrac{5}{15}=\dfrac{1}{3}\)

25 tháng 3 2022

Cần chi tiết hum bẹn

25 tháng 3 2022

có nha

a) Ta có: \(\dfrac{-5}{7}\left(\dfrac{14}{5}-\dfrac{7}{10}\right):\left|-\dfrac{2}{3}\right|-\dfrac{3}{4}\left(\dfrac{8}{9}+\dfrac{16}{3}\right)+\dfrac{10}{3}\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\)

\(=\dfrac{-5}{7}\cdot\dfrac{3}{2}\cdot\dfrac{21}{10}-\dfrac{3}{4}\cdot\dfrac{56}{3}+\dfrac{10}{3}\cdot\dfrac{8}{15}\)

\(=\dfrac{-9}{4}-14+\dfrac{16}{9}\)

\(=\dfrac{-1621}{126}\)

b) Ta có: \(\dfrac{17}{-26}\cdot\left(\dfrac{1}{6}-\dfrac{5}{3}\right):\dfrac{17}{13}-\dfrac{20}{3}\left(\dfrac{2}{5}-\dfrac{1}{4}\right)+\dfrac{2}{3}\left(\dfrac{6}{5}-\dfrac{9}{2}\right)\)

\(=\dfrac{-17}{26}\cdot\dfrac{13}{17}\cdot\dfrac{-3}{2}-\dfrac{20}{3}\cdot\dfrac{3}{20}+\dfrac{2}{3}\cdot\dfrac{-33}{10}\)

\(=\dfrac{3}{4}-1-\dfrac{11}{5}\)

\(=-\dfrac{49}{20}\)

3 tháng 3 2023

`4/7+4`

`=4/7+4/1`

`=4/7+28/7`

`=32/7`

__

`3+6/11`

`=33/11+6/11`

`=39/11`

__

`3-5/7`

`=3/1-5/7`

`=21/7-5/7`

`=16/7`

__

`21/9-2`

`=21/9-18/9`

`=3/9`

`=1/3`

__

`15/24+2`

`=15/24+48/24`

`=63/24`

`=21/16`

__

`63/45-20/25`

`=63/45-4/5`

`=63/45-36/45`

`=27/45`

`=9/15`

__

`3/4-2/8`

`=3/4-1/4`

`=2/4`

__

`6/7-5/8`

`=48/56-35/56`

`=13/56`

__

`37/45-5/9`

`=37/45-25/45`

`=12/45`

`=4/15`

__

`46/39-11/13`

`=46/39-33/39`

`=13/39`

`=1/2`

__

`5/12+3/4+1/3`

`=5/12+9/12+4/12`

`=14/12+4/12`

`=18/12`

`=3/2`

__

`1/2+3/7+11/14`

`=7/14+6/14+11/14`

`=13/14+11/14`

`=24/14`

`=12/7`

__

`7/10-(1/5+1/4)`

`=7/10-(4/20+5/20)`

`=7/10-9/20`

`=14/20-9/20`

`=5/20`

`=1/4`

__

`15/4-2/3-3/4`

`=(15/4-3/4)-2/3`

`=12/4-2/3`

`=3-2/3`

`=9/3-2/3`

`=7/3`

1 tháng 2

câu 1) 

\(\dfrac{-12}{18}+\left(\dfrac{-21}{35}\right)=\dfrac{-19}{15}\)
câu 2) 

\(-\dfrac{3}{21}+\dfrac{6}{42}=0\)
câu 3)

\(-\dfrac{18}{24}+\dfrac{15}{21}=-\dfrac{1}{28}\)
câu 4) 

\(\dfrac{1}{6}+\dfrac{2}{5}=\dfrac{17}{30}\)
câu 5) 

\(\dfrac{3}{5}+\left(-\dfrac{7}{4}\right)=-\dfrac{23}{20}\)
câu 6) 

\(\left(-2\right)+\left(\dfrac{-5}{8}\right)=\dfrac{-21}{8}\)
câu 7) 

\(\dfrac{1}{-8}+\left(-\dfrac{5}{9}\right)=-\dfrac{49}{72}\)
câu 8) 

\(\dfrac{4}{13}+\dfrac{12}{39}=\dfrac{8}{13}\)
câu 9) 

\(\dfrac{1}{21}+\dfrac{1}{28}=\dfrac{1}{12}\)
câu 10) 

\(-\dfrac{3}{29}+\dfrac{16}{58}=\dfrac{5}{29}\)
câu 11) 

\(\dfrac{8}{40}+\left(-\dfrac{36}{45}\right)=-\dfrac{3}{5}\)
câu 12) 

\(-\dfrac{8}{18}+\left(-\dfrac{15}{27}\right)=-1\)
câu 13) 

\(\dfrac{13}{30}+\left(-\dfrac{1}{5}\right)=\dfrac{7}{30}\)
câu 14) 

\(\dfrac{2}{21}+\dfrac{1}{28}=\dfrac{11}{84}\)
câu 15) 

\(5+\left(-\dfrac{3}{4}\right)=\dfrac{17}{4}\)
câu 16) 

\(\dfrac{18}{24}+\dfrac{45}{-10}=-\dfrac{15}{4}\)