Thực hiện phép tính

11/12+11/20+11/30+11/42+11/56+11/72

`11/12+11/20+11/30+11/42+11/56+11/72`

`= 11 . (1/12 + 1/20 + 1/30 + 1/42 + 1/56 + 1/72)`

`= 11 . (1/(3 . 4) + 1/(4 . 5) + 1/(5 . 6) + 1/(6 . 7) + 1/(7 . 8) + 1/(8 . 9) )`

`= 11 . (1/3 - 1/4 + 1/4 - 1/5 + 1/5 - 1/6 + 1/6 - 1/7 + 1/7 - 1/8 + 1/8 - 1/9)`

`= 11 . (1/3 - 1/9)`

`= 11 . 2/9`

`= (11 . 2)/9`

`= 22/9`

`@Zero`