Đáp án:

Giải thích các bước giải:

`l) 6,72 × 12 + 3,36 × 75 + 3,36`

`= 3,36 × 2 × 12 + 3,36 × 75 + 3,36`

`= 3,36 × ( 2 × 12 + 75 + 1 )`

`= 3,36 × ( 24 + 75 + 1 )`

`= 3,36 × 100 = 336`

`k) 476,5 × 99 + 476 + 0,5`

`= 476,5 × 99 + ( 476 + 0,5 )`

`= 476,5 × 99 + 476,5`

`= 476,5 × ( 99 + 1 )`

`= 476,5 × 100 = 47650`

`p) 78,4 × 9 + 78 + 0,4`

`= 78,4 × 9 + ( 78 + 0,4 )`

`= 78,4 × 9 + 78,4`

`= 78,4 × ( 9 + 1 )`

`= 78,4 × 10 = 784`

`m) 3/( 11 × 14 ) + 3/( 14 × 17 ) + 3/( 17 × 20 ) + 3/( 20 × 23 ) + 3/( 23 × 26 )`

`= 1/11 - 1/14 + 1/14 - 1/17 + 1/17 - 1/20 + 1/20 - 1/23 + 1/23 - 1/26`

`= 1/11 - 1/26`

`= 26/286 - 11/286`

`= 15/286`

`e) 4/( 3 × 6 ) + 4/( 6 × 9 ) + 4/( 9 × 12 ) + 4/( 12 × 15 ) + 4/( 15 × 18 )`

`= 4/3 × ( 3/( 3 × 6 ) + 3/( 6 × 9 ) + 3/( 9 × 12 ) + 3/( 12 × 15 ) + 3/( 15 × 18 ) )`

`= 4/3 × ( 1/3 - 1/6 + 1/6 - 1/9 + 1/9 - 1/12 + 1/12 - 1/15 + 1/15 - 1/18 )`

`= 4/3 × ( 1/3- 1/18 )`

`= 4/3 × 5/18`

`= ( 4 ×5 )/( 3 × 18 )`

`= 10/27`

`text{promax123}`

`text{Đáp án :}`

`text{i)6,72 x 12 + 3,36 x 75 + 3,36}`

`text{= 3,36 x 2 x 12 + 3,36 x 75 + 3,36 x 1}`

`text{= 3,36 x 24 + 3,36 x 75 + 3,36 x 1}`

`text{= 3,36 x ( 24 + 75 + 1 )}`

`text{= 3,36 x 100}`

`text{= 336}`

`text{k) 476,5 x 99 + 476 + 0,5}`

`text{= 476,5 x 99 + 476,5}`

`text{= 476,5 x 99 + 476,5x1}`

`text{= 476,5 x ( 99 + 1 )}`

`text{= 476,5 x 100}`

`text{= 47650}`

`text{p) 78,4 x 9 + 78 + 0,4}`

`text{78,4 x 9 + 78,4}`

`text{78,4 x 9 + 78,4 x 1}`

`text{78,4 x ( 9 + 1 )}`

`text{78,4 x 10}`

`text{784}`

`text{Sorry bạn, phần m và n mình chưa làm được, xin bạn thông cảm}`