*Lời giải :
`A = 11 . 3/13 - (2 . 4/7 + 5 . 3/13)`
`-> A = 11 . 3/13 - 2 . 4/7 - 5 . 3/13`
`-> A = [11 . 3/13 - 5 . 3/13] - 2 . 4/7`
`-> A = [3/13 . (11 - 5)] - 2 . 4/7`
`-> A = [3/13 . 6] - 2 . 4/7`
`-> A = 18/13 - 8/7`
`-> A = 22/91`
Vậy `A = 22/91`