Question

28 ×78+28 ×22

75 × 27+75 ×72+75

8064:64 ×37

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

Answer 1

\(28\times78+28\times22\\ =28\times\left(78+22\right)\\ =28\times100\\ =2800\)

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\(75\times27+75\times72+75\\=75\times\left(27+72+1\right)\\ =75\times100\\ =7500\)

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\(8064:64\times37\\ =126\times37\\ =4662\)

 

Answer 2

`28 xx 78 + 28 xx 22`

`= 28 xx ( 78+22)`

`=28xx100`

`=2800`

____________________

`75 xx 27 + 75 xx 72 + 75`

`= 75 xx 27 + 75 xx 72 + 75xx1`

`=75xx(27+72+1)`

`=75xx100`

`=7500`

______________________________

`8064 : 64 xx 37`

`=126xx37`

`=4662`

______________________________

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

`=12 : { 390 : [ 500 - ( 160 - 7 )]}`

`=12 : { 390 : [ 500 - 153]`

`=12 : { 390 : 347}`

`=12 : 390/347`

`=12 xx 347/390`

`=694/65`

Answer 3

28 ×78+28 ×22=\(28x\left(78+22\right)=28x100=2800\)

75 × 27+75 ×72+75=\(75x\left(27+72+1\right)=75x100=7500\)

8064:64 ×37\(=126x37=126x\left(40-3\right)=126x40-126x3\)

\(=5040-378=4662\)

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

\(=12:\left\{390:\left[500-\left(160-7\right)\right]\right\}\)

\(=12:\left\{390:\left[500-153\right]\right\}\)

\(=12:\left\{390:347\right\}\)

\(=12:\dfrac{390}{347}=12x\dfrac{347}{390}=\dfrac{12x347}{390}=\dfrac{6x2x347}{6x65}=\dfrac{694}{65}\)( chả bt sau đề ko mà số hơi lớn)

 

 

 

Answer 4

\(=\)\(28 ×78+28 ×22\)

\(=\)\(28 ×(78+22 )\)

\(=\)\(28 ×100=2800\)

\(-----------\)

\(75 × 27+75 ×72+75\)

\(=75 ×( 27+72+1)\)

\(=75 ×100=7500\)

\(-----------\)

\(8064:64 ×37\)

\( = 126 x 37\)

\(= 4662\)

\(------------\)

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

 12 : { 390 : [ 500 - { 125 + 245 } ]

12 : { 390 : [ 500 - 370 ] } 

 12 : { 390 : 130 }

12 : 3=4