\(\dfrac{13}{10}\)

=11/3-7/6-6/5

=110/30-35/30-36/30

=39/30=13/10

Hướng dẫn giải:

\(\dfrac{1}{12}+\dfrac{55}{2}x\dfrac{2}{5}=\dfrac{1}{12}+11=\dfrac{1}{12}+\dfrac{132}{12}=\dfrac{133}{12}\)

a) {132 - [116- (16 - 8)]:2}.5

= [132 - (116 - 8): 2] .5

= (132 - 108 : 2). 54

= (132 - 54).5

= 78.5 = 390

b) 36: {136 : 200 - (12+ 8. 20)]}

= 36: {336 : [200 - ( 12 + 160)]}

= 36 : [336 : ( 200 - 172)

= 36 : ( 336 : 28) = 3

c) 86 - [15. (64 - 39): 75+11] 

= 86 - (15.25 : 75 + 11) 

= 86 - ( 5 + 11) 

= 70

d)  55 - [ 49 - ( 2 3 . 17 - 2 3 . 14 ) ]

= 55 - 49 - 2 3 . 3

= 55- ( 49 - 24)

= 30

Bạn ơi ở chỗ trước số 200 có dấu này [mà

a) {132 – [116 – (16 – 8)]:2}.5

= [132 – (116 – 8): 2] .5

= (132 – 108 : 2). 5

= (132 –54).5

= 78.5 = 390

b) 36: {136 : 200 – (12+ 8. 20)]}

= 36: {336 : [200 – ( 12 + 160)]}

= 36 : [336 : ( 200 – 172)

= 36 : ( 336 : 28)

= 36 : 12 = 3

c) 86 – [15. (64 - 39): 75+11]

= 86 – (15.25 : 75 + 11)

= 86 – ( 5 + 11)

= 70.

d) 55 – [49 – (2³ . 17 – 2³.14)]

= 55 – (49 – 2³ .3)

= 55 – ( 49 – 24)

= 30

Đáp án: 199

55 : 5 + 87 = 11 + 87 = 98

Đáp án cần chọn là B

a) ( 12 + 21 - 23 ) - ( 23 - 21 + 10 )

  = 12 + 21 - 23 - 23 - 21 + 10

  = ( 12 + 10 ) - ( 21 - 21 ) - ( 23 - 23 )

  =        22      -        0        -        0

  =                          22

b) ( 55 + 45 + 15 ) - ( 15 - 55 + 45 )

  = 55 + 45 + 15 - 15 - 55 + 45

  = ( 55 + 45 ) + ( 55 + 45 ) + ( 15 - 15)

  =       100      +      100      +      0

  =                          200

\(a)\)\(-\left(12+21-23\right)-\left(23-21+10\right)\)

 \(=-12-21+23-23+21-10\)

 \(=\left(-21+21\right)+23-23-12-10\)

 \(=0+0-12-10\)

 \(=-22\)

\(b)\)\(\left(55+45+15\right)-\left(15-55+45\right)\)

  \(=55+45+15-15+55-45\)

  \(=\left(15-15\right)+\left(45-45\right)+55+55\)

  \(=0+0+55+55\)

  \(=110\)

`4/5 - (6/15 + 1/5)`

`=4/5 - (6/15 + 3/15)`

`= 4/5 - 9/15`

`= 4/5 -3/5`

`=1/5`

4/5 - (6/15 + 1/5)

= 4/5 - (6/15 + 3/15)

= 4/5 - 3/5

= 1/5