`a)`

`117 × ( 36 + 62 ) - 17 × ( 62 + 36 )`

`= 117 × 98 - 17 × 98`

`= 98 × (117 - 17)`

`= 98 × 100 `

`= 9800`

`b)`

`(145 × 99 + 145) - (143 × 101 -143)`

`= 145 × 99 + 145 - (143 × 101 - 143)`

`= 145 × ( 99 + 1) - 143 × (101 - 1)`

`= 145 × 100 - 143 × 100`

`= 14500 - 14300`

`= 200`

`c)`

 `2009 × 867 + 2009 × 133`

`= 2009 × ( 867 + 133 )`

`= 2009 × 1000`

`= 2009000`

`d)`

`2008 × 167 - 2008 × 67`

`= 2008 × ( 167 - 67 )`

`= 2008 × 100`

`= 200800`

`@Tobi`

Đáp án`+`Giải thích các bước giải:

a) `117 x (36+62)-17 x (62+36)`

`= 117 x 98-17 x 98`

`= 98 . (117 - 17)`

`= 98 . 100`

`= 9800`

b) `(145 x 99 +145)-(143 x 101 - 143)`

`= 145 . (99 + 1) - 143 . (101 - 1)`

`= 100 . (145 - 143)`

`= 100 . 2`

`= 200`

c) `2009 x 867 + 2009 x 133`

`= 2009 . (867 + 133)`

`= 2009 . 1000`

`= 2009000`

d) `2008 x 167-2008 x 67`

`= 2008 . (167 - 67)`

`= 2008 . 100`

`= 200800`

$\color{#1c1c1c}{\text{c}}$$\color{#363636}{\text{o}}$$\color{#4f4f4f} {\text{d}}$$\color{#696969}{\text{e}}$$\color{#828282} {\text{r}}$$\color{#9c9c9c}{\text{2}}$$\color{#b5b5b5} {\text{k}}$$\color{#cfcfcf}{\text{1}}$$\color{#eee9e9}{\text{2}}$