a) 6857 + 3444 : 28

=6857 + 123

=6980

b) 80 - [ 130 - ( 75 - 11 ) ]

=80 - [ 130 - 64 ]

=80 - 66

=14

c) 100 : { 2 x [ 52 - ( 35 - 8 ) ]}

=100 : { 2 x [ 52 - 27 ]}

=100 : { 2 x 25 }

=100 : 50

=2

d) 12 : { 390 : [ 500 - ( 125 + 35 + 7 x 30 ) ] }

=12 : { 390 : [ 500 - ( 125 + 35 + 210 ) ] }

=12 : { 390 : [ 500 - 370 ] }

=12 : { 390 : 130 }

=12 : 3

=4

a) 6857 + 3444 : 28

=6857 + 123

=6980

b) 80 - [ 130 - ( 75 - 11 ) ]

=80 - [ 130 - 64 ]

=80 - 66

=14

c) 100 : { 2 x [ 52 - ( 35 - 8 ) ]}

=100 : { 2 x [ 52 - 27 ]}

=100 : { 2 x 25 }

=100 : 50

=2

d) 12 : { 390 : [ 500 - ( 125 + 35 + 7 x 30 ) ] }

=12 : { 390 : [ 500 - ( 125 + 35 + 210 ) ] }

=12 : { 390 : [ 500 - 370 ] }

=12 : { 390 : 130 }

=12 : 3

=4

Câu b chép sai đề rùi kìa 

a)

80 - [ 130 - ( 75 - 11) ]

= 80 - [ 130 - 64 ]

= 80 - 66

= 14

A) \(80-\left[120-\left(75-11\right)\right]=80-\left(120-75+11\right)=80-56=24\)

B) \(12:390:\left[500-\left(125+35+7.30\right)\right]=12:390:\left(500-370\right)=12:390:130=\frac{1}{4225}\)

a/ 100 : { 2. [ 52 - ( 35 - 8 )]}

= 100 : { 2. [ 52 -  27 ]}

= 100 : { 2. 25 }

= 100 : 50

= 2

b/ 12 : { 390 : [ 500 - ( 125 + 35 . 7 )]}

= 12 : { 390 : [ 500 - ( 125 + 245 )]}

= 12 : { 390 : [ 500 - 370  ]}

= 12 : { 390 : 130 }

= 12 : 3

= 4

c/ 3. 5² - 16 : 2²

= 3 . 25 - 16 : 4

= 75 - 4

= 71

    Bài này dễ mà 

a: \(=28\cdot100=2800\)

12 : ( 390 : ( 500 - ( 125 +35 x 7 )

= 12 : (390 : (500 - (125 + 245) ) )

= 12 : (390 : ( 500 - 370 ) )

= 12 : ( 390 : 130 )

= 12 : 3

= 4 

\(12:\left(390:\left(500-\left(125+35\times7\right)\right)\right)\)

\(=12:\left(390:\left(500-370\right)\right)\)

\(=12:\left(390:130\right)\)

\(=12:3\)

\(=4\)

Ta có A = 12 : { 390 : [ 500 - 370 ]}

= 12 : { 390 : 130 }

= 12 : 3

= 4

12:(390:(500-(125+245)))

=12:(390:(500-370))

=12:(390:130)

=12:3

=4

12 : { 390 : [ 500 - ( 125 + 35 x 7 ) ] }

= 12 : { 390 : [ 500 - ( 125 + 245 ) ] }

= 12 : { 390 : [ 500 - 370 ) ] }

= 12 : { 390 : 130 }

= 12 : 3

= 4

Hok tốt

\(100:\left\{2\cdot\left[22-\left(35-8\right)\right]\right\}\\ =100:\left\{2\cdot\left[22-27\right]\right\}\\ =100:\left(-10\right)\\ =-10\)

\(12:\left\{390:\left[500-\left(125+35\cdot7\right)\right]\right\}\\ =12:\left\{390:\left[500-370\right]\right\}\\ =12:3\\ =4\)

a) 100:{ 2.[22-(35-8)]}

=100:{2.[22-27]}

=100:{2.(-5)}

=100: 10

=10

a) -10

b)4

các bạn ơi xin các bạn tội ngiệp cho tôi vài lik eSky Nguyễn

a).

= 27. (75+25)- 150

= 27. 100 -150

= 2700    - 150

= 2550

a)80-[130-(12-40)²]         b)27.75+25.27-150             c)12:{390:[500-(125+35.7)]}

=80-[130-(-28)²]             =27.(75+25)-150                 =12:{390:[500-(125+245)]}

=80-[130-784]                =27.100-150                       =12:{390:[500-370]}

=80-(-654)                     =2700-150                          =12:{390:130}

=80+654                       =2550                                =12:3

=734                                                                      =4

Nhớ **** thanks so much^__^