Ta có: A = 12 : {390 : [500 - 370)]}

= 12 : {390 : 130}

=12 : 3

=4 

Ta có: A = 12 : {390 : [500 - 370)]}

= 12 : {390 : 130}

=12 : 3

=4 

A=12:{390:[500-(125+35x7)]}

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

=12:{390:[500-370]

=12:{390:130}

=12:3

=4

12:{390:[500-125+35x7]}

=12:{390:620}

=12:39/62

=248/13

cám ơn nhé !

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

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

\(=12:\left\{390:870\right\}\)

\(=12:\frac{13}{29}\)

\(=\frac{348}{13}\)

248/13

248/13

12:{390:[500-125+35x7]}

=12:{390:620}

=12:39/62

=248/13

a. \(678\times\left(276+49\right)-678\times\left(149+76\right)\)

\(=678\times\left[\left(276+49\right)-\left(149+76\right)\right]\)

\(=678\times\left(276+49-149-76\right)\)

\(=678\times\left(200-100\right)\)

\(=67800\)

b. \(23\times157+15\times46-28\times87\)

\(=3611+690-2436\)

\(=1865\)

c. \(12:\left\{390:\left[500-\left(125+35\times7\right)\right]\right\}\)

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

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

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

\(=12:3\)

\(=4\)

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

= 12 : { 390 : [ 500-  370 ] }

= 12 : { 390 : 130 }

= 12 : 3

= 4 

12:{390:[500-(125+357)]}=12:{390:[500-482]}=12:{390:18}=12:65/3=36/65

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

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

=12:{390:130}

=12:3

=4 

tick cho mình nhé mình trước

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

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

   =   12 : { 390 : [ 500 - 370 ] }

   =   12 : { 390 : 130 }

    =   12 : 3

    =     4

đề bài sai

sai đề bạn nhé

\(\frac{-214}{65}\)