4/9.8/15+4/19.7/15-4/9

=4/9.(8/15+7/15)-4/9

=4/9.1-4/9

=4/9-4/9

=0

câu a : 

\(\dfrac{-8}{24}+\dfrac{-4}{12}=\dfrac{-1}{3}+\dfrac{-1}{3}=\dfrac{-2}{3}\)

câu b : 

\(\dfrac{-20}{35}+\dfrac{16}{24}=\dfrac{-4}{7}+\dfrac{2}{3}=\dfrac{2}{21}\)

câu c : 

\(\dfrac{-3}{9}+\dfrac{-6}{15}=\dfrac{-1}{3}+\dfrac{-2}{5}=\dfrac{-11}{15}\)

câu d : 

\(\dfrac{3}{13}-\dfrac{4}{10}=\dfrac{3}{13}-\dfrac{2}{5}=\dfrac{-11}{65}\)

câu e : 

\(\dfrac{5}{17}-\dfrac{9}{15}=\dfrac{5}{17}-\dfrac{3}{5}=\dfrac{-26}{85}\)

câu g : 

\(\dfrac{9}{18}-\dfrac{6}{15}+\dfrac{3}{-9}=\dfrac{9}{18}-\dfrac{6}{15}+\dfrac{-3}{9}\\ =\dfrac{1}{2}-\dfrac{2}{5}+\dfrac{-1}{3}=\dfrac{-7}{30}\)

câu h : 

\(\dfrac{5}{4}-\dfrac{1}{2}+\dfrac{-7}{8}=\dfrac{10}{8}-\dfrac{4}{8}+\dfrac{-7}{8}=\dfrac{-1}{8}\)

a)15/8:9/8/7/8;3/8

b)3/5;7/15;4/15;8/45

c)9/4;47/10;4/5;3/8

a) \(\frac{3}{8},\frac{15}{8},\frac{9}{8},\frac{7}{8}\)

Từ lớn -> bé:

=>\(\frac{15}{8},\frac{9}{8},\frac{7}{8},\frac{3}{8}\)

b) \(\frac{4}{15},\frac{3}{5},\frac{8}{45},\frac{7}{15}=\frac{12}{45},\frac{27}{45},\frac{8}{45},\frac{21}{45}\)

Từ lớn -> bé:

=> \(\frac{3}{5},\frac{7}{15},\frac{4}{15},\frac{8}{45}\)

c) \(\frac{3}{8},\frac{4}{5},\frac{47}{40},\frac{9}{4}=\frac{15}{40},\frac{32}{40},\frac{47}{40},\frac{90}{40}\)

Từ lớn -> bé:

=>\(\frac{9}{4},\frac{47}{40},\frac{4}{5},\frac{3}{8}\)

minh ko biet

= 8 /17 *[ 20/15 + 4/15 - 9/15

=8/17 * 1 

8 /17

\(\frac{3}{9}+\frac{9}{15}+\frac{8}{12}=\frac{1}{3}+\frac{3}{5}+\frac{2}{3}=\left(\frac{1}{3}+\frac{2}{3}\right)+\frac{3}{5}=1+\frac{3}{5}=\frac{8}{5}\)

\(\frac{4}{10}+\frac{12}{32}+\frac{9}{15}=\frac{2}{5}+\frac{3}{8}+\frac{3}{5}=\left(\frac{2}{5}+\frac{3}{5}\right)+\frac{3}{8}=1+\frac{3}{8}=\frac{11}{8}\)

\(\left(\frac{4}{10}-\frac{8}{30}\right)\times\frac{6}{8}=\frac{2}{15}\times\frac{3}{4}=\frac{6}{60}=\frac{1}{10}\)

a, 3/9+9/15+8/12=1/3+3/5+2/3=14/15+2/3=8/5

a = <

b= <

c = >

d : =

a) <

b) <

c) >

d) bằng

<

<

<

=

Dấu * là dấu nhân nhà m.ng ai giúp mik mik k k chừa 1 ai :3

\(\frac{5}{6}+\frac{3}{4}< \frac{19}{11}\)

\(\frac{17}{12}-\frac{9}{8}< \frac{1}{3}\)

\(\frac{4}{9}\times\frac{6}{5}=\frac{8}{15}\)

\(\frac{15}{4}:\frac{3}{8}>8\)

\(\frac{5}{6}+\frac{3}{4}=\frac{19}{12}< \frac{19}{11}\) 

\(\frac{17}{12}-\frac{9}{8}=\frac{7}{24}< \frac{1}{3}=\frac{8}{24}\) 

\(\frac{4}{9}\cdot\frac{6}{5}=\frac{24}{45}=\frac{8}{15}\)

\(\frac{15}{4}:\frac{3}{8}=\frac{15}{4}\cdot\frac{8}{3}=\frac{5}{2}=2\frac{1}{2}< 8\)

`-5/9+7/15-4/9+3/12+8/15`

`=(-5/9-4/9)+(7/15+8/15)+3/12`

`=-9/9+15/15+3/12`

`=-1+1+3/12`

`=0+3/12`

`=3/12`

`=1/4`

\(12:\frac{4}{9}-8\frac{8}{15}:\frac{4}{9}=12.\frac{9}{4}-\frac{128}{15}.\frac{9}{4}=\frac{9}{4}\left(12-\frac{128}{15}\right)\)

\(=\frac{9}{4}.\frac{52}{15}=\frac{39}{5}\)

=(12- 88/15 ): 4/9 

=(180/15 - 88/15 ): 4/9

=92/15 *9/4

= 39/5

\(12:\frac{4}{9}-8\frac{8}{15}:\frac{4}{9}=\left[12-8\frac{8}{15}\right]:\frac{4}{9}=\left[12-\left(8+\frac{8}{15}\right)\right].\frac{9}{4}\)

\(=\left[12-8-\frac{8}{15}\right].\frac{9}{4}=\left[4-\frac{8}{15}\right].\frac{9}{4}=\frac{52}{15}.\frac{9}{4}=\frac{39}{5}=7\frac{4}{5}\)