a)27.75+25.27-150

=27.(75+25)-150

=27.100-150

=2700-150

=2550

\(a,27.75+25.27-150\)

\(=27.\left(75+25\right)-150\)

\(=27.100-150\)

\(=2700-150\)

\(=2550\)

\(b,12:\left\{390:\left[500-\left(125+35.7\right)\right]\right\}\)

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

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

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

\(=12:3\)

\(=4\)

a) 27 . 75 + 25 . 27 - 150 = 2025 + 675 - 150 = 2700 - 150 = 2550.

Lưu ý. Có thể dùng tính chất phân phối của phép nhân đối với phép cộng để nhẩm:

27 . 75 + 25 . 27 - 150 = 27 . (75 + 25) - 150 = 27 . 100 - 150 = 2700 - 150 = 2550.

b) 12 : {390 : [500 - (125 + 35 . 7)]} = 12 : {390 : [500 - (125 + 245)]}

= 12 : [390 : (500 - 370)] = 12 : (390 : 130) = 12 : 3 = 4.

a,27+75.25+27-150

= 27.(75+25)-150

=27.100-150

=2700-150

=2550

b,12:{390:[500-(125+35.7)]}

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

=12:{390:[500-370]}

=12:{390:130}

=12:3

=4

Thank you very much

a, 25.(75 + 27 - 150 )

= 25 . (-48)

= - 1200

b, 12 : { 390 : [500 - 370 ]

= 12 : { 390 : 130 }

= 12 : 3

= 4

a) \(27.75+25.27-150\)

\(=27.\left(75+25\right)-150\)

\(=27.100-150\)

\(=2700-150\)

\(=2550\)

b) \(12:\left\{390:\left[500-\left(125+35.7\right)\right]\right\}\)

\(=12:\left\{390:\left[500-370\right]\right\}\)

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

\(=12:3\)

\(=4\)

a, = 27 . ( 75 + 25 ) - 150 
    = 27 . 100 - 150
    = 2700 - 150
    = 2550
b, = 12 : { 390 : [ 500 - 370 ]
    = 12 : { 390 : 130 }
    = 12 : 3 
    = 4
 

a) 27.75+25.27-150=2025+675-150

                            =2700-150

                            =2550

b) 12:{390:[500-(125+35.7)]}=12:{390:[500-(125+245)]}

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

                                        =12:(390:130)

                                        =12:3

                                        =4

a) \(27\cdot75+25\cdot27-150\)

\(=27\cdot\left(75+25\right)-150\)

\(=27\cdot100-150\)

\(=2700-150\)

\(=2550\)

b) \(12:\left\{390:\left|500-\left(125+35\cdot7\right)\right|\right\}\)

\(=12:\left\{390:\left|500-\left(125+245\right)\right|\right\}\)

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

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

\(=12:3\)

\(=3\)

a) 27.(75+25)-150=27.100-150=2550

a. 27 . 75 + 25 . 27 - 150

= 27. ( 75 + 25 ) - 150

= 2700 - 150

= 2550

b. 12 :  1390  : [ 500 - ( 125 + 35 .7 ) ]}

Câu này sai đề bài bạn nhé

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^__^

\(a.25.\left(75+25\right)-150.\)

\(=25.100-150\)

\(=2500-150=2350\)

\(b.12:\left\{390:\left[500-\left(125+245\right)\right]\right\}\)

\(=12\left\{390:\left[500-370\right]\right\}\)

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

\(=12:3=4\)

a) 27 . 75 + 25 . 27 - 150

= 27 . ( 75 + 25 ) - 150

= 27 . 100 - 150

= 2700 - 150

= 2550

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

= 12 : {390 : [500 - (125 + 245 ) ] }

= 12 : {390 : [500 - 370 ] }

= 12 : {390 : 130 }

= 12 : 3

= 4