A= 3/5.6/7+3/5.3/7-3/5.2/7

A= 3/5. (6/7+3/7-2/7) = 3/5

B= (-13.2/5+-2/9.2/5+2/5.11/9).5/2

B= (-13-2/9+11/9).2/5.5/2

B= -13+(11/9-2/9)= -12

C= (-4/5+5/7).3/2+(-1/5+2/7).3/2

C= (-4/5+5/7+-1/5+2/7).3/2

C= ((-4/5+-1/5)+(5/7+2/7)).3/2

C= 0

D= 4/9.-5/3+4/9.-22/3

D= 4/9.110/9

D= 440/81

.

rêtrt

A= 5/4

B= 63/52

a) = 1/2 + 1/3 = 5/6

b) = 2/5 + 2/3 = 16/15

c) = 7/11 . ( 3/4 + 1/4 ) + 4/11

= 7/11 . 1 + 4/11

= 7/11 + 4/11

= 1

d) = ( 3/4 + 1/2 + 1/4 ) . 8/3

= 3/2 . 8/3

= 4

1−12+13=6−3+26=561−12+13=6−3+26=56.

25+35:910=25+35⋅109=25+23=161525+35:910=25+35⋅109=25+23=1615.

711⋅34+711⋅14+411=711(34+14)+411=711+411=1711⋅34+711⋅14+411=711(34+14)+411=711+411=1.

(34+0

Câu 1.

a) 1-\(\dfrac{1}{2}\)+\(\dfrac{1}{3}\)= \(\dfrac{1}{2}\)+\(\dfrac{1}{3}\)=\(\dfrac{3}{6}\)+\(\dfrac{2}{6}\)=\(\dfrac{5}{6}\)

b) \(\dfrac{2}{5}\)+\(\dfrac{3}{5}\):\(\dfrac{9}{10}\)= 1 :\(\dfrac{9}{10}\)= \(\dfrac{10}{9}\)

c) ​​\(\dfrac{7}{11}\).\(\dfrac{3}{4}\)+\(\dfrac{7}{11}\).\(\dfrac{1}{4}\)+\(\dfrac{4}{11}\)=\(\dfrac{7}{11}\).1+\(\dfrac{4}{11}\)=1

`(6/11 +5/11) xx 3/7`

`= 11/11xx 3/7`

`=1xx3/7`

`=3/7`

__

`3/5 xx 7/9 - 3/5 xx 2/9`

`= 3/5 xx (7/9-2/9)`

`= 3/5 xx 5/9`

`= 15/45`

`= 1/3`

__

`(6/7 -4/7):2/5`

`= 2/7 : 2/5`

`= 2/7 xx 5/2`

`= 10/14`

`= 5/7`

\(\left(\dfrac{6}{11}+\dfrac{5}{11}\right)\times\dfrac{3}{7}\)

\(=1\times\dfrac{3}{7}=\dfrac{3}{7}\)

___________

\(\dfrac{3}{5}\times\dfrac{7}{9}-\dfrac{3}{5}\times\dfrac{2}{9}\)

\(=\dfrac{3}{5}\times\left(\dfrac{7}{9}-\dfrac{2}{9}\right)\)

\(=\dfrac{3}{5}\times\dfrac{5}{9}\)

\(=\dfrac{1}{3}\)

__________

\(\left(\dfrac{6}{7}-\dfrac{4}{7}\right):\dfrac{2}{5}\)

\(=\dfrac{2}{7}\times\dfrac{5}{2}\)

\(=\dfrac{5}{7}\)

\(#WendyDang\)

\(\left(\dfrac{6}{11}+\dfrac{5}{11}\right)\times\dfrac{3}{7}\)

\(=\dfrac{11}{11}\times\dfrac{3}{7}\\ =1\times\dfrac{3}{7}=\dfrac{3}{7}\)

_____

\(\dfrac{3}{5}\times\dfrac{7}{9}-\dfrac{3}{5}\times\dfrac{2}{9}\\ =\dfrac{3}{5}\times\left(\dfrac{7}{9}-\dfrac{2}{9}\right)\\ =\dfrac{3}{5}\times\dfrac{5}{9}\\ =\dfrac{3}{9}\\ =\dfrac{1}{3}\)

_________

\(\left(\dfrac{6}{7}-\dfrac{4}{7}\right):\dfrac{2}{5}\\ =\dfrac{2}{7}\times\dfrac{5}{2}\\ =\dfrac{10}{14}\\ =\dfrac{5}{7}\)

\(A=11\dfrac{3}{13}-\left(2\dfrac{4}{7}+5\dfrac{3}{13}\right)\)

\(A=11\dfrac{3}{13}-5\dfrac{3}{13}-2\dfrac{4}{7}\)

\(A=6-2\dfrac{4}{7}\)

\(A=5\dfrac{7}{7}-2\dfrac{4}{7}\)

\(A=3\dfrac{3}{7}\)

\(B=\left(6\dfrac{4}{9}+3\dfrac{7}{11}\right)-4\dfrac{4}{9}\)

\(B=\left(6\dfrac{4}{9}-4\dfrac{4}{9}\right)+3\dfrac{7}{11}\)

\(B=2+3\dfrac{7}{11}\)

\(B=5\dfrac{7}{11}\)

\(C=\dfrac{-5}{7}.\dfrac{2}{11}+\dfrac{-5}{7}-\dfrac{9}{11}+1\dfrac{5}{7}\)

\(C=\dfrac{-5}{7}.\left(\dfrac{2}{11}+1\right)-\dfrac{9}{11}+1\dfrac{5}{7}\)

\(C=\dfrac{-5}{7}.\dfrac{13}{11}-\dfrac{9}{11}+1\dfrac{5}{7}\)

\(C=\dfrac{-65}{77}-\dfrac{9}{11}+1\dfrac{5}{7}\)

\(C=\dfrac{4}{11}+1\dfrac{5}{7}\)

\(C=\dfrac{160}{11}\)

\(D=0,7.2\dfrac{2}{3}.20.0,375.\dfrac{5}{28}\)

\(D=\dfrac{7}{10}.\dfrac{8}{3}.20.\dfrac{375}{1000}.\dfrac{5}{28}\)

\(D=\dfrac{7}{28}=\dfrac{5}{2}\)

\(E=\left(-6,17+3\dfrac{5}{9}-2\dfrac{36}{97}\right)\left(\dfrac{1}{3}-0,25-\dfrac{1}{12}\right)\)

\(E=\left(-6,17+3\dfrac{5}{9}-2\dfrac{36}{97}\right)\left(\dfrac{1}{3}-\dfrac{1}{4}-\dfrac{1}{12}\right)\)

\(E=\left(-6,17+3\dfrac{5}{9}-2\dfrac{36}{97}\right)\left(\dfrac{1}{12}-\dfrac{1}{12}\right)\)

\(E=\left(-6,17+3\dfrac{5}{9}-2\dfrac{36}{97}\right).0\)

\(\Rightarrow E=0\)

Sửa đề : \(M=\left(\dfrac{\dfrac{2}{5}-\dfrac{2}{9}+\dfrac{2}{11}}{\dfrac{7}{5}-\dfrac{7}{9}+\dfrac{7}{11}}-\dfrac{\dfrac{1}{3}-\dfrac{1}{3}+\dfrac{1}{5}}{1\dfrac{1}{6}-\dfrac{7}{6}+\dfrac{7}{10}}\right):\dfrac{2021}{2022}\)

\(M=\left(\dfrac{\dfrac{2}{5}-\dfrac{2}{9}+\dfrac{2}{11}}{\dfrac{7}{5}-\dfrac{7}{9}+\dfrac{7}{11}}-\dfrac{\dfrac{1}{3}-\dfrac{1}{3}+\dfrac{1}{5}}{1\dfrac{1}{6}-\dfrac{7}{6}+\dfrac{7}{10}}\right):\dfrac{2021}{2022}\\ =\left(\dfrac{2\left(\dfrac{1}{5}-\dfrac{1}{9}+\dfrac{1}{11}\right)}{7\left(\dfrac{1}{5}-\dfrac{1}{9}+\dfrac{7}{11}\right)}-\dfrac{\dfrac{1}{3}-\dfrac{1}{3}+\dfrac{1}{5}}{\dfrac{7}{6}-\dfrac{7}{6}+\dfrac{7}{10}}\right):\dfrac{2021}{2022}\\ =\left(\dfrac{2}{7}-\dfrac{\dfrac{1}{3}-\dfrac{1}{3}+\dfrac{1}{5}}{\dfrac{7}{2}\left(\dfrac{1}{3}-\dfrac{1}{3}+\dfrac{1}{5}\right)}\right):\dfrac{2021}{2020}\\ =\left(\dfrac{2}{7}-\dfrac{2}{7}\right):\dfrac{2021}{2022}=0\)

A= 4/7.

Biết có cái

1.\(\dfrac{4}{5}\)

2.\(\dfrac{2}{3}\)

3.\(\dfrac{39}{55}\)

a) \(\dfrac{3}{5}\times\dfrac{2}{3}:\dfrac{1}{2}=\dfrac{3}{5}\times\dfrac{2}{3}\times2=\dfrac{6}{15}\times2=\dfrac{12}{15}=\dfrac{4}{5}\)

b) \(\dfrac{2}{3}\cdot\dfrac{1}{2}+\dfrac{1}{3}=\dfrac{1}{3}+\dfrac{1}{3}=\dfrac{2}{3}\)

c) \(\left(\dfrac{5}{7}+\dfrac{2}{5}\right):\dfrac{11}{7}=\left(\dfrac{25}{35}+\dfrac{14}{35}\right)\cdot\dfrac{7}{11}=\dfrac{39}{35}\cdot\dfrac{7}{11}=\dfrac{273}{385}=\dfrac{39}{55}\)

a) = \(\dfrac{6}{15}\) \(\div\dfrac{1}{2}=\) \(\dfrac{12}{15}\) rút gọn = \(\dfrac{4}{5}\)

b) = \(\dfrac{2}{6}+\dfrac{1}{3}\) = \(\dfrac{6}{18}+\dfrac{6}{18}\) = \(\dfrac{12}{18}\) = \(\dfrac{2}{3}\)

c) = \(\dfrac{5}{7}+\dfrac{2}{5}=\dfrac{25}{35}+\dfrac{14}{35}=\dfrac{39}{35}\) \(\div\dfrac{11}{7}=\dfrac{39}{35}\)