a: \(=28\cdot100=2800\)

= 12 : {390 : [500 - (125 + 245)]}

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

= 12 : (390 : 130)

= 12 : 3

= 4

Số cần tìm là:

 4 

  Đ/S: 4

chúc bn học tốt

bằng  4 nha nhé các bạn

Đ/S : 4

k mk nha Huyền

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

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

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

=12:{390:130}

=12:3

=4

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

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

      \(=12:\left[390:130\right]\)

      \(=12:3=4\)

kết quả là 3

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

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

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

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

= 12 : (390 : 130)

= 12 : 3

= 4

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

\(a,27.75+25.27-150\)

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

\(=27.100-150\)

\(=2700-150\)

\(=2550\)

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

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

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

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

\(=12:3\)

\(=4\)

a) \(27\cdot75+25\cdot27-150\)

\(=27\cdot100-150\)

\(=2700-150\)

\(=2550\)

b) \(12\div\left\{390\div\left[500-\left(125+35\cdot7\right)\right]\right\}\)

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

\(=12\div\left(390\div130\right)\)

\(=12\div3\)

\(=4\)