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a) \(\dfrac{8}{9}-\dfrac{3}{4}=\dfrac{32}{36}-\dfrac{27}{36}=\dfrac{5}{36}\)

b) \(\dfrac{2}{3}+\dfrac{3}{4}=\dfrac{8}{12}+\dfrac{9}{12}=\dfrac{17}{12}\)

c) \(\left(\dfrac{1}{2}-\dfrac{2}{5}\right)\times\dfrac{5}{6}=\dfrac{1}{10}\times\dfrac{5}{6}=\dfrac{5}{60}=\dfrac{1}{12}\)

d) \(\left(\dfrac{4}{3}-\dfrac{1}{6}\right):\dfrac{7}{3}=\dfrac{7}{6}:\dfrac{7}{3}=\dfrac{7}{6}\times\dfrac{3}{7}=\dfrac{1}{2}\)

24 tháng 2 2022

a) \(\dfrac{8}{9}-\dfrac{3}{4}=\dfrac{32}{36}-\dfrac{27}{36}=\dfrac{5}{36}\)

b) \(\dfrac{2}{3}+\dfrac{3}{4}=\dfrac{8}{12}+\dfrac{9}{12}=\dfrac{17}{12}\)

c) \(\left(\dfrac{1}{2}-\dfrac{2}{5}\right)\times\dfrac{5}{6}=\left(\dfrac{5}{10}-\dfrac{4}{10}\right)\times\dfrac{5}{6}=\dfrac{1}{10}\times\dfrac{5}{6}=\dfrac{1}{12}\)

d) \(\left(\dfrac{4}{3}-\dfrac{1}{6}\right):\dfrac{7}{3}=\left(\dfrac{8}{6}-\dfrac{1}{6}\right):\dfrac{7}{3}=\dfrac{7}{6}\times\dfrac{3}{7}=\dfrac{1}{2}\)

11 tháng 2 2023

`#lv`

`-2/5+(-7/10)-9/6`

`=-2/5-7/10-9/6`

`=-4/10-7/10-9/6`

`=-11/10-3/2`

`=-11/10-15/10`

`=-26/10`

`=-13/5`

__

`1/2+(-2/5)-(-2/3)`

`=1/2-2/5+2/3`

`=5/10-4/10+2/3`

`=1/10+2/3`

`=3/30+20/30`

`=23/30`

__

`5/3-3/4+7/6`

`=20/12-9/12+14/12`

`=11/12+14/12`

`=25/12`

__

`-1/5+5/3-3/2`

`=-3/15+25/15-3/2`

`=22/15-3/2`

`=44/30-45/30`

`=-1/30`

__

`1/4-7/8+(-9/10)`

`=2/8-7/8-9/10`

`=-5/8-9/10`

`=-25/40-36/40`

`=-61/40`

__

`5/4+1/2+(-7/12)`

`=15/12+6/12-7/12`

`=21/12-7/12`

`=14/12`

`=7/6`

__

`-5/8-1/3+(-7/6)`

`=-5/8-1/3-7/6`

`=-15/24-8/24-28/24`

`=-52/24`

`=-13/6`

__

`-3/4-7/10+(-5/6)`

`=-3/4-7/10-5/6`

`=-45/60-42/60-50/60`

`=-137/60`

11 tháng 2 2023

Bài làm

a, (-2/5) + (-7/10) - 9/6 =(-12/30) + (-21/30) - 45/30=(-33/30) - 45/30 = (-78/30)

b,1/2 + (-2/5) - (-2/3) = 15/30 + (-12/30) - (-20/30) = 3/30 - (-20/30) = 23/30

c,5/3 - 3/4 + 7/6 = 40/24 - 18/24 + 28/24 = 22/24 + 28/24 = 50/24 = 25/12

d, (-1/5) + 5/3 - 3/2 = (-6/30) + 50/30 - 45/30 = 44/30 - 45/30 = (-1/30)

e, 1/4 - 7/8 + (-9/10) = 10/40 - 35/40 - 36/40 = (-25/40) - 36/40 = (-61/40)

f, 5/4 +1/2 + (-7/12) = 15/12 + 6/12 - 7/12 = 21/12 - 7/12 = 14/127/6

g,(-5/8) -1/3 + (-7/6) = (-15/24) - 8/24 - 28/24 = (-23/24) - 28/24 = (-51/24) 

k,(-3/4) - 7/10 + (-5/6) = (-45/60) - 42/60 - 50/60 = (-87/60) - 50/60 = (-137/60)

chúc bn học tốt nha

sai thì mn góp ý giúp mk

 

a: \(\dfrac{-8}{3}\cdot\dfrac{15}{24}=\dfrac{-8}{24}\cdot\dfrac{15}{3}=\dfrac{-1}{3}\cdot5=-\dfrac{5}{3}\)

b: \(=\dfrac{3}{4}\cdot\dfrac{1}{-9}=\dfrac{-1}{12}\)

c: \(x=-\dfrac{7}{6}+\dfrac{5}{8}=-\dfrac{13}{24}\)

d: \(x=-\dfrac{14}{25}-\dfrac{3}{4}=\dfrac{-56-75}{100}=\dfrac{-131}{100}\)

13 tháng 4 2023

a) \(\dfrac{-3}{20}\) + \(\dfrac{-7}{4}\) =\(\dfrac{-3}{20}\) + \(\dfrac{-35}{20}\) = -2

b) 6 và \(\dfrac{2}{3}\) - 4 và \(\dfrac{2}{3}\) = 2

c) \(\dfrac{-3}{10}\) + \(\dfrac{7}{12}\) = \(\dfrac{-18}{60}\) + \(\dfrac{35}{60}\) =\(\dfrac{17}{60}\)

d) \(\dfrac{35}{-9}\) . \(\dfrac{81}{7}\) = \(\dfrac{-35}{9}\) . \(\dfrac{81}{7}\) = 45

e) \(\dfrac{-2}{5}\) - \(\dfrac{-3}{4}\) = \(\dfrac{-8}{20}\) - \(\dfrac{-15}{20}\) = \(\dfrac{-8}{20}\) + \(\dfrac{15}{20}\) =\(\dfrac{7}{20}\)

f) \(\dfrac{5}{23}\) . \(\dfrac{7}{26}\) + \(\dfrac{5}{23}\) .\(\dfrac{9}{26}\) = \(\dfrac{5}{23}\) .  ( \(\dfrac{7}{26}\) + \(\dfrac{9}{26}\) )= \(\dfrac{5}{23}\) . \(\dfrac{8}{13}\) = \(\dfrac{40}{299}\)

g) \(\dfrac{-3}{12}\) : \(\dfrac{4}{15}\) =\(\dfrac{-3}{12}\) . \(\dfrac{15}{4}\) =\(\dfrac{-5}{8}\)

h) 1 và \(\dfrac{1}{6}\) - 3 và \(\dfrac{1}{3}\) =\(\dfrac{7}{6}\) -\(\dfrac{10}{3}\) = \(\dfrac{-13}{6}\)

i) \(\dfrac{-2}{5}\) . (-3) + \(\dfrac{3}{8}\) . \(\dfrac{4}{-10}\) =(\(\dfrac{-2}{5}\) .\(\dfrac{-4}{10}\)) + [(-3) . \(\dfrac{3}{8}\) 

                                     = \(\dfrac{4}{25}\) + \(\dfrac{-9}{8}\) = \(\dfrac{32}{200}\) + \(\dfrac{-225}{200}\)  = \(\dfrac{-193}{200}\)

j) \(\dfrac{-13}{17}\) + (\(\dfrac{13}{-21}\) + \(\dfrac{-4}{17}\) )

= ( \(\dfrac{-13}{17}\) + \(\dfrac{-4}{17}\) )+\(\dfrac{-13}{21}\) 

= -1+\(\dfrac{-13}{21}\)

\(\dfrac{-21}{21}\) + \(\dfrac{-13}{21}\) = \(\dfrac{-34}{21}\)

Khôi nguyễn

 

 

13 tháng 4 2023

sao tính nổi:))

 

a) \(\dfrac{29}{60}\)

b)\(1\dfrac{23}{25}\)

c) \(2\dfrac{26}{35}\)

6 tháng 4 2022

A.2/5 và 3/2 = 4/10 và 15/10

B1/4 và 5/6 = 6/24 và 20/24

C5/9 và 1/6 = 30/54 và 9/54

D.3/8 và 7/6 = 18/48 và 56/48

Bài 7:

7.1: I là trung điểm của AB

=>\(AB=2\cdot IA=4\left(cm\right)\)

7.2:

C nằm giữa A và B

=>AC+CB=AB

=>CB=10-8=2(cm)

C là trung điểm của NB

=>NC=CB=2cm

C là trung điểm của NB

=>\(NB=2\cdot NC=2\cdot2=4\left(cm\right)\)

Bài 6:

a: \(\dfrac{4}{5}=\dfrac{4\cdot6}{5\cdot6}=\dfrac{24}{30}\)

\(\dfrac{8}{15}=\dfrac{8\cdot2}{15\cdot2}=\dfrac{16}{30}\)

\(-\dfrac{3}{2}=\dfrac{-3\cdot15}{2\cdot15}=-\dfrac{45}{30}\)

b: \(2=\dfrac{2\cdot45}{45}=\dfrac{90}{45}\)

\(\dfrac{-10}{5}=\dfrac{-10\cdot9}{5\cdot9}=\dfrac{-90}{45}\)

\(\dfrac{7}{-9}=\dfrac{-7}{9}=\dfrac{-7\cdot5}{9\cdot5}=\dfrac{-35}{45}\)

c: \(\dfrac{3}{-2}=\dfrac{-3}{2}=\dfrac{-3\cdot6}{2\cdot6}=\dfrac{-18}{12}\)

\(\dfrac{5}{-6}=\dfrac{-5}{6}=\dfrac{-5\cdot2}{6\cdot2}=\dfrac{-10}{12}\)

\(\dfrac{-6}{4}=\dfrac{-6\cdot3}{4\cdot3}=\dfrac{-18}{12}\)

d: \(-\dfrac{1}{2}=\dfrac{-1\cdot15}{2\cdot15}=\dfrac{-15}{30}\)

\(\dfrac{4}{3}=\dfrac{4\cdot10}{3\cdot10}=\dfrac{40}{30}\)

\(\dfrac{6}{-5}=\dfrac{-6}{5}=\dfrac{-6\cdot6}{5\cdot6}=\dfrac{-36}{30}\)

bài 5:

a: \(\dfrac{3}{4}=\dfrac{9}{12};\dfrac{-3}{12}=\dfrac{-3}{12};\dfrac{-2}{3}=-\dfrac{8}{12};\dfrac{-1}{-6}=\dfrac{1}{6}=\dfrac{2}{12}\)

mà -8<-3<2<9

nên \(-\dfrac{8}{12}< -\dfrac{3}{12}< \dfrac{2}{12}< \dfrac{9}{12}\)

=>\(\dfrac{-2}{3}< \dfrac{-3}{12}< \dfrac{-1}{-6}< \dfrac{3}{4}\)

b: Ta có: \(\dfrac{-7}{9}=\dfrac{-28}{36};\dfrac{-1}{3}=\dfrac{-12}{36};-1=-\dfrac{36}{36}\)

mà -36<-28<-12

nên \(-1< -\dfrac{28}{36}< -\dfrac{12}{36}\)

=>\(-1< \dfrac{-7}{9}< -\dfrac{1}{3}< 0\)

\(\dfrac{5}{12}=\dfrac{15}{36};\dfrac{-1}{-4}=\dfrac{1}{4}=\dfrac{9}{36}\)

mà 9<15

nên \(0< \dfrac{1}{4}< \dfrac{5}{12}\)

=>\(-1< -\dfrac{7}{9}< -\dfrac{1}{3}< 0< \dfrac{1}{4}< \dfrac{5}{12}\)

c: \(\dfrac{-1}{-2};0;\dfrac{3}{10};1;\dfrac{-2}{-5};\dfrac{3}{-4}\)

\(-\dfrac{3}{4}< 0\)

\(\dfrac{-1}{-2}=\dfrac{1}{2}=\dfrac{5}{10};\dfrac{3}{10}=\dfrac{3}{10};1=\dfrac{10}{10};\dfrac{-2}{-5}=\dfrac{4}{10}\)

mà 3<4<5<10

nên \(\dfrac{3}{10}< \dfrac{4}{10}< \dfrac{5}{10}< \dfrac{10}{10}\)

=>\(0< \dfrac{3}{10}< \dfrac{-2}{-5}< \dfrac{-1}{-2}< 1\)

=>\(-\dfrac{3}{4}< 0< \dfrac{3}{10}< \dfrac{-2}{-5}< \dfrac{-1}{-2}< 1\)

d: \(-\dfrac{37}{150}=\dfrac{-37}{150};\dfrac{17}{-50}=\dfrac{-17}{50}=\dfrac{-51}{150}\)

\(\dfrac{23}{-25}=\dfrac{-23}{25}=\dfrac{-138}{150};\dfrac{-7}{10}=\dfrac{-105}{150};\dfrac{-2}{5}=-\dfrac{60}{150}\)

mà -138<-105<-60<-51<-37

nên \(-\dfrac{138}{150}< -\dfrac{105}{150}< -\dfrac{60}{150}< -\dfrac{51}{150}< -\dfrac{37}{150}\)

=>\(\dfrac{23}{-25}< \dfrac{-7}{10}< \dfrac{-2}{5}< \dfrac{-17}{50}< \dfrac{37}{-150}\)

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

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

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

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